Behind the scenes, however, a bit of drama was unfolding. When the stars were resigning their contracts for season 11 and season 12 (the last two of the show), there were multiple negotiations being discussed.
The show’s star actors Jim Parsons, Johnny Galecki, and Kaley Cuoco negotiated with CBS together and became the highest-paid actors. Mayim Bialik and Melissa Rauch who joined during season 3 and became regulars a year later, also negotiated together and waited to be paid the same amount as the originals. The five co-stars agreed to a $100,000 pay cut per episode in order for the two actresses to receive the salaries that they deserve.
Now that the "Big Bang Theory" is done, it is interesting to see how much the whole cast has changed since. This show led the actors to major success and wealth. Let’s look at how the cast has transformed as well as the increase in their salaries!
John Galecki as Leonard Hofstadter – Then
We met Leonard during season 1 when he worked as an experimental physicist and Sheldon Cooper’s roommate and best friend. He loves Sheldon but often gets annoyed by his eccentricity.
Leonard is super smart, like the rest of his friends, and has a Ph.D. from Princeton, which he finished when he was the ripe age of 24. He fell in love with Penny, who has dreams of being an actress, and the two eventually tied the knot in the ninth season.
John Galecki as Leonard Hofstadter – Now
TBBT wasn’t John’s first acting gig, but it did make his name a well-known one. He now has several awards in his arsenal, including an Emmy for Outstanding Lead Actor in a Comedy Series.
John has since starred in other movies and television shows, but none have brought him success, like his role in this show. John’s role as Leonard made him a salary of $350,000 per episode until the 8th season, following a whopping increase to $900,000 per episode.
Jim Parsons as Sheldon Cooper – Then
Sheldon has been a fan favorite since the start of the show. He is a Caltech theoretical physicist and was once roommates with Leonard, his best friend. He easily annoys those around him, has a very serious demeanor, and is anal about his routine.
He rocks his geekiness and his arrogance, believing himself to be perfect. He started dating neurobiologist Amy in season 5, and they become engaged in season 10.
Jim Parsons as Sheldon Cooper – Now
Jim is another star of the show who found himself blossoming in his role as the beloved Sheldon. He has taken home a Golden Globe and an Emmy for his work.
You may have recognized his voice in the animated movie "Home," where he plays an eccentric and freethinking alien named Oh. Jim made $900,000 per episode (along with John and Kaley), making him one of the highest-paid actors in comedy television.
Sara Gilbert as Leslie Winkle – Then
Leslie works at Caltech with Leonard as a physicist. Leslie is a female carbon copy of Leonard, even dressing similarly in hoodie sweatshirts and black-framed glasses. In season 1, Leonard asked her out instead of Penny because he felt like Penny was too good of a catch for him.
Sheldon disapproves of their relationship, causing ongoing tension between the two. Ultimately, Leslie and Howard form a casual, no-strings-attached relationship, with Howard having emotional feelings towards her.
Sara Gilbert as Leslie Winkle – Now
Sara was and still is best known for her long-time role as Darlene Conner on "Roseanne." The actress now has 3 children and is married to Linda Perry.
"The Conners," a spinoff of "Roseanne," aired in 2018. The "Roseanne" reboot was canceled following a controversial tweet by star and executive producer Roseanne Barr.
Mayim Bialik as Amy Fowler – Then
Amy started on the show during the season 3 finale, where she meets Sheldon. Raj and Howard found her on a dating site and figured that this neurobiologist would be a great fit for Sheldon.
The two date until becoming engaged (with a short break in between) in season 10. Amy is also in Penny’s posse with Penny and Bernadette.
Mayim Bialik as Amy Fowler – Now
Mayim started acting at age 12, eventually landing her most famed role as Amy in TBBT. She is a neuroscientist in real life, so playing the role wasn’t much of a change.
When the actress is signed on for the 12th season, she received a raise and now earning $500,000 per episode. She now stars as the titular character in another sitcom titled "Call Me Kat."
Simon Helberg as Howard Wolowitz – Then
Simon plays the role of Howard, who is an aerospace engineer and astronaut who has made impressive scientific gains. Howard’s mother is very overprotective.
At the start of the show, Howard hangs with everyone at Leonard and Sheldon’s apartment. During season 3, he meets Bernadette, who worked at the time at The Cheesecake Factory with Penny and was pursuing her Ph.D. in microbiology. Howard and Bernadette make it official in season 5 and have two kids — Halley and Neil.
Simon Helberg as Howard Wolowitz – Now
Simon has been starring on the show in a lead role from the very beginning. Other acting jobs he has done include recently acting as Cosme McMoon in the movie "Florence Foster Jenkins" alongside Meryl Streep and Hugh Grant.
He also played the voice of Bian Zao in "Kung Fu Panda: Legends of Awesomeness" from 2011-2016. He makes $750,000 per episode, which is less than what other leads make, however still very admirable.
Laura Spencer as Emily Sweeney – Then
Emily, who works as a dermatologist, met Raj during season 7 on his online dating site. Raj dates Emily and Lucy at the same time. Emily isn’t bothered by it, but Lucy is. Raj likes Emily because of her sadistic sense of humor and fondness for horror films.
Raj and Emily date seriously, with Raj eventually breaking up with her to be with Claire. At one point, Raj dates Emily and Claire at the same time and then breaks up with both girls during season 10.
Laura Spencer as Emily Sweeney – Now
Laura played Emily in TBBT while also playing the role of Jessica in "Bones." She also played the role of Christine in the short 2017 film "Vitality."
After "Bones," the actress's appearances became few and far between, but she hasn't gone off the radar completely.
Kunal Nayyar as Rajesh Koothrappali – Then
Raj, an astrophysicist, has been on the show since season 1, where he played Howard’s BFF. He also used to spend all of his time hanging out in Leonard and Sheldon’s apartment, along with Howard.
During the first half of the series, Raj’s social anxiety was a major barrier to forming relationships with women. After the sixth season, he became more confident and began to date various women. In season 9, he even found himself caught in between two different women.
Kunal Nayyar as Rajesh Koothrappali – Now
Kunal is most known for his role as Raj in TBBT. However, he has done some other acting aside from the show. He starred as Tony in the movie "Dr. Cabbie" and played the voice of Guy Diamond in the DreamWorks animated film "Trolls."
He made $750,000 per episode, which really isn’t bad. He keeps acting, mainly in small roles, but hasn't done anything very big after the show ended.
Kevin Sussman as Stuart Bloom – Then
Stuart makes his first appearance during the second season, where he works as the owner of The Comic Center of Pasadena.
Stuart connects with Raj in season 6 when Howard leaves for space. Single, lonely, and depressed, he often feels left out from the guys and looks for constant reassurance from them. He also deals with some financial trouble.
Kevin Sussman as Stuart Bloom – Now
Kevin didn’t make his debut in TBBT. In 2001, he starred in Spielberg’s "A.I. Artificial Intelligence," playing the role of Supernerd.
The actor is financially successful, despite his character on the sitcom having financial issues. His income wasn't as high as some of the other costars; however, he still managed $50,000 per episode.
Alessandra Torresani as Claire – Then
Claire works as a screenwriter and bartender. She meets Raj and Howard at the comic book store. She wants Raj to write a script with her for a children’s science fiction movie.
Raj is into her, but Claire has no interest in him. Raj breaks up with Emily in order to pursue Claire, which only further repulses her. At one point, Claire does have an interest in Raj, who begins to date both Claire and Emily simultaneously, eventually breaking up with both women.
Alessandra Torresani as Claire – Now
Torresani was cast in various small parts before being chosen to play the part of Claire in TBBT. Among her gigs, you can find the series "Husbands," "Two and a Half Men," and "American Horror Story."
She played the role of Amber in the movie called "Step Sisters" in 2018 but hasn't done much since.
Aarti Mann as Priya Koothrappali – Then
Priya plays the part of Raj’s younger sister. She is a law student who we meet during the 4th season. She dates Leonard, and the two don’t tell Raj, who eventually finds out.
Priya agrees to continue to date Leonard under the condition that he cuts off contact with Penny. When Priya’s parents find out about the relationship, they are extremely disappointed and force her to return home. The couple has a long-distance relationship for some time, ultimately finding it frustrating and breaking their loyalty to one another.
Aarti Mann as Priya Koothrappali – Now
The actress has been cast in several TV series since TBBT. She played Dr. DaSilva in the rom-com drama "I’ll See You in My Dreams," as well as María Monroe in "Suits" and Agent Laura Kenney in "Scandal."
Recently, she played the part of Holly Harner in an episode of "Grey’s Anatomy" and filmed a drama called "Love Sonia," playing the part of Jiah.
Sara Rue as Stephanie Barnett – Then
Stephanie works as a doctor and highly distinguished surgical resident at Fremont Memorial Hospital. She is introduced in season 2 when Howard tries to seduce her and allows her to drive a Mars Rover.
Instead, Stephanie meets and falls for Leonard, and the pair ends up dating. Stephanie moves all of her belongings into Leonard’s apartment, and Leonard soon ends their relationship through a text message.
Sara Rue as Stephanie Barnett – Now
Sara has been cast in multiple TV shows since her role as Stephanie. She played Kim Sallinger in "Malibu Country," Brenda in "Rules of Engagement," and Candace in "Mom."
She's also had regular roles in the TV shows "A Series of Unfortunate Events," "American Housewife," and "B Positive."
Margo Harshman as Alex Jensen – Then
Alex is pursuing her Ph.D. in Caltech Physics and works as Sheldon’s assistant. Sheldon often gives her tasks that are unrelated to their research.
Alex wants Leonard and asks him on a date, but Leonard says no because of his loyalty to Penny.
Margo Harshman as Alex Jensen – Now
Margo’s acting career didn’t start in TBBT, rather back when she was a kid in "Even Stevens," playing the role of Tawny Dean, the best friend of was Shia LaBeouf’s character, Louis Stevens.
Margo has played several smaller parts since TBBT, like Alison Kidman in "Bones" and Delilah Fielding in "NCIS."
Brian Patrick Wade as Kurt – Then
Kurt plays the role of Penny’s former boyfriend. The two lived together after Penny moved from Nebraska to California.
Kurt, unlike the guys, isn’t very bright, but he’s a tall, muscular, and formidable guy. Kurt and Leonard naturally have some beef, and it takes Penny some time to get over Kurt, although she finds him to be a jerk.
Brian Patrick Wade as Kurt – Now
Brian has played several roles in TV and movies before his role in TBBT. He acted as Mitch Lyons in "The Guardian" and Fatneck in "Bring It On Again."
He also played small parts in "Two and a Half Men," "Arrested Development," "Teen Wolf," and "Agents of Shield." At the moment, he is taking a break from acting and working as a personal trainer.
Valerie Azlynn as Alicia – Then
Alicia is Leonard, Penny, and Sheldon’s former neighbor who lives in the apartment above them. She first meets Leonard and Sheldon in the lobby, where Sheldon bombards her with annoying questions. Annoyed, Alicia nonetheless answers every question, and Sheldon accepts her.
Leonard, Howard, and Raj swoon over her, doing her many favors. Penny is annoyed that Alicia is taking advantage of the boys and jealous. Penny tells the boys that Alicia is using them. The two get into a quarrel after Penny confronts Alicia about this, resulting in Penny’s black eye and the boys stopping to do things for Alicia.
Valerie Azlynn as Alicia – Now
Valerie has been acting long before her gig on TBBT. She played the role of Damien’s assistant in the comedy "Tropic Thunder," along with Ben Stiller.
In 2012 she played Melanie Sutton in the series "Sullivan & Son." Today, she continues to play small roles in TV series and films.
Brooke D’Orsay as Christy Vanderbel – Then
Christy is a former friend of Penny from Nebraska who was engaged to Penny’s cousin while sleeping with Penny’s brother Randall. Penny thinks of her as a family member and lets her stay with her for a short time.
Christy hooks up with Howard in Penny’s room and drives Penny out of her own apartment. Christy is very materialistic, and she goes out with Howard under the condition that he buys her stuff. After confronting Howard’s mother, who threatens to take Howard out of his will if they keep dating, she dumps him.
Brooke D’Orsay as Christy Vanderbel – Now
Brooke has acted in multiple series since her role as Christy in TBBT. She acted as Heather Hanson in the comedy series "Happy Hour." She also was in an episode of "How I Met Your Mother." She was the voice of Caitlin in the animated series "6Teen" for 86 episodes.
She played two different characters in "Two and a Half Men" — in 2007, she played Robin, and in 2014, she played Kate. Later, she played the role of Paige Collins in the show "Royal Pains." Her last two gigs were minor parts in TV movies.
Riki Lindhome as Ramona Nowitzki – Then
Ramona works at Caltech as a postdoctoral researcher and is a big fan of Sheldon and his work. She meets him in the cafeteria, and they arrange to have dinner at his apartment.
His friends feel that she is a bit obsessive, but Sheldon just appreciates that he’s getting free dinner. During their date, the rest of the gang sits on the couch as onlookers of this strange turn of events. Eventually, Sheldon solves the problem that he’s working on, and Ramona wants to share credit for it. He reacts by kicking her out of the apartment.
Riki Lindhome as Ramonda Nowitzki – Now
Riki’s most well-known roles are in the movies "Million Dollar Baby" and "The Last House on the Left." She has played Beatrice in the historical comedy series "Another Period" from 2013 to 2018. She also was the voice of the character Poison Ivy in the newest "Lego Batman Movie."
The actress also acted in a thriller movie called "Under the Silver Lake," alongside Andrew Garfield and Riley Keough (Elvis’s granddaughter).
Eliza Dushku as Angela Page – Then
Angela is an FBI agent who does a background check on Howard when he needs a security clearance to be on the Defense Department Equipped Surveillance Satellite Team.
When she interviews Raj about Howard, Raj is paranoid and only talks about himself, sharing with her that he is definitely legal in the U.S. Then, Leonard hits on her but learns that she is married to a Navy Seal. When Angela interviews Sheldon, he accidentally tells her that Howard once crashed the Mars rover to try and impress a girl. Needless to say, Howard didn’t pass the security clearance to be on the team.
Eliza Dushku as Angela Page – Now
Eliza definitely didn’t start her career in TBBT. When she made her appearance on the series, she was already a well-known name in Hollywood.
She played Missy Pantone in the popular cheerleading movie "Bring It On," as well as Faith in the "Angel" and "Buffy the Vampire Slayer" Series. She had a lead role in the Fox series "Dollhouse" as Echo and another lead as Tru in "True Calling." She hasn't been acting since 2017.
Courtney Henggeler as Missy Cooper – Then
Missy is Sheldon’s fraternal twin sister, who is completely different than her brother. While she is very charming and amicable, Sheldon is anything but. She is introduced in the first season, with Leonard, Howard, and Raj all crushing on her.
The men fall over each other, trying to win her attention, and Sheldon tells them that he will choose who gets to date her. Missy finds an ally with Penny, and while they are hanging out at her apartment, each of the guys tries their luck at asking her out, but none of them are successful.
Courtney Henggeler as Missy Cooper – Now
"The Big Bang Theory" was one of Courtney’s first acting roles. Since the gig, she has acted in a few other — mostly minor — roles.
In 2013-2015, she acted as Claudia in the hit CBS sitcom "Mom," where she acted alongside Anna Faris and Allison Janney. In 2018, she became a series regular as Amanda LaRusso in the Netflix hit "Cobra Kai."
John Ross Bowie as Barry Kripke – Then
Barry Kripke Ph.D. is a Caltech plasma-physicist-turned-string-theorist and Leonard and Sheldon’s colleague. He is impressively smart and has Rhotacism, which is also kind of cute, but he can be obnoxious, knowing exactly how to tick people off.
Nonetheless, he is quite talented and therefore appreciated (even if not entirely liked) by Sheldon, Howard, Leonard, and Raj. He first appeared in the show during season 2 and has kept appearing in later seasons as well.
John Ross Bowie – Now
John is most well known for his part on TBBT, but he has made himself well known even outside of the series.
He is a regular sketch comedy performer and is very present in the world of comedy, both writing and performing sketches. He has also acted in several films such as "He’s Just Not That Into You" and "What the Bleep Do We Know?"
Wil Wheaton as Wil Wheaton – Then
Wil Wheaton plays himself in the TBBT from seasons 1 to 11. A little acting was required, as he had to play a darker version of himself.
For some time, he had some turf with Sheldon, but the two reconciled in season 5 and became good friends.
Wil Wheaton – Now
Richard William ‘Wil’ Wheaton III seems to do it all. He’s an actor, T.V. personality, voice actor, writer, and blogger. He has acted in "Star Trek: The Next Generation," "Stand By Me," "Toy Soldiers," "Legion of Superheroes," and "Eureka."
On top of all of this, he is also the co-creator and host of the YouTube show "TableTop," which is a web-series about games.
Laurie Metcalf as Mary Cooper – Then
Thankfully to Mary Cooper, Sheldon Cooper, the genius himself, is alive. Mary Cooper is Sheldon’s mother.
Mary Cooper and Sheldon Cooper are very different. Mary is a born-again devout Christian who constantly checks up on her son and tries to knock some sense into him (usually following a phone call from Leonard).
Laurie Metcalf – Now
Laurie Metcalf has had an extensive career with some impressive roles on big TV shows. She has acted in "Roseanne," "Desperate Housewives," "Getting On," and "The McCarthy’s."
Given her part in "Rosanne," she is currently reprising her role as Jackie Harris in the show's spinoff, "The Conners."
Christine Baranski as Dr. Beverly Hofstadter – Then
With the last name Hofstadter, Dr. Beverly Hofstadter is so clearly the mother of Leonard.
She has appeared in sixteen episodes of the show, but not all of them were filmed in the studio, as her character's presence was sometimes only required over video chat. Nice work from home job, huh?
Christine Baranski – Now
Similar to many actors and actresses alike, Christine studied at the respected Juilliard School. She has influenced the acting world with her formal and respectable appearance and voice.
Christine Baranski is a very talented actress and has used her talents both on stage and on screen. The two-time Tony winner has also appeared in the movie adaptation of "Mamma Mia," starred in the hit series "The Good Fight," and is constantly working on new projects.
Ian Scott Rudolph as Captain Sweatpants – Then
While Captain Sweatpants doesn’t have a clearly defined role perse or even a proper name, he is still a part of "The Big Bang Theory."
He is known as Captain Sweatpants, a name that comes from the fact that he’s always seen wearing sweatpants and an iconic superhero t-shirt. Appearing He can be seen in the comic book store most of the time and was part of seasons 2 to 7.
Ian Scott Rudolph – Now
If you saw Ian Scott Rudolph on the street, you probably wouldn’t be in much awe. The actor has only played small roles in T.V. series.
Besides TBBT, he also appeared in "The Middle." He didn’t even receive credit for his work as Captain Sweatpants until season 7. We still love you, Captain Sweatpants.
Brian George as Dr. V.M Koothrappali – Then
Dr. V.M Koothrappali has played a somewhat controversial role on "The Big Bang Theory," but through it all, we love him.
He plays the role of Raj’s father and works as a successful gynecologist in New Delhi, India. We mostly see him on video chat with his wife. He makes his first physical appearance in season 8, in ‘The Clean Room Infiltration.’ Hey, doc!
Brian George as Dr. V.M Koothrappali – Now
Much like his character in TBBT, in real life, Brian George’s life is also varied. He was born in Jerusalem and has since lived in Israel, London and currently lives in Toronto, Canada.
He studied theater and performing arts at the University of Toronto and has been working in comedy and drama, on-screen and as a voice-over talent, since 1976. In 1997, he landed a big acting gig on "Austin Powers: International Man of Mystery." He is recognized for his role as Babu Bhatt on "Seinfeld" and his role on "The Big Bang Theory."
Alice Amter as Mrs. Koothrappali – Then
Meet Dr. Koothrappali’s wife (for a few seasons before she became his ex-wife). We never learn Mrs. Koothrappali’s first name, and we see her only through video chat, just like her husband.
We know that she used to work as a healthcare employee in New Delhi. She has made an appearance in seasons 1 to 5 and in seasons 8. Her character is definitely a memorable one!
Alice Amter Mrs. Koothrappali – Now
Funnily enough, Alice Amter has moved around a lot, just like her on-screen husband. The English actress has lived in multiple countries, including England, Germany, France, Japan, and the United States.
Alice Amter moved in her 30’s to Los Angeles in order to pursue acting. She played the role of Dr. Kapoor in "Hot in Cleveland." She is most recognized for her role in "The Big Bang Theory."
Casey Sander as Mike Rostenkowski – Then
Meeting parents is never easy, especially when that parent is Mike Rostenkowski. Mike plays Bernadette’s father and Howard’s father-in-law.
Mike is a hardened and retired police officer. Bernadette warns Howard about mentioning Jimmy Carter, organic food, gun control, and foreigners. We see him in seasons 5,6,7, and 9.
Casey Sander as Mike Rostenkowski – Now
While Casey Sandler may not have the recognition that some of the other actors on this list have, he still has a pretty impressive resume.
He has appeared on numerous TV series, including "Malcolm in the Middle," "Hunter," "Buffy the Vampire Slayer," "Criminal Minds," "Mad Men," "Rules of Engagement," "Sons of Anarchy," just to name a few. On a side note, Casey Sander went to school with Richard Karn, and the two were good friends. We would love to meet him!
Vernee Watson-Johnson as Althea – Then
While you may not remember this character, she actually had some pretty memorable moments in the series. Althea works as a nurse in the hospital throughout the series, managing the sperm bank, the patient’s floor, and the emergency room.
Vernee`s character is both sarcastic and serious at the same time. Althea was also one of the only characters with Sheldon and Leonard to be transferred from the unaired pilot to the series. Points for Althea!
Vernee Watson-Johnson as Althea – Now
Vernee Watson-Johnson is a very talented actress, voice artist, author, and acting coach, and it seems like she does it all. She is recognized for her part in "The Big Bang Theory" but has other claims to fame.
Many fans know her as Verna Jean Williams on the popular show, "Welcome Back, Kotter" and as Will Smith’s mother in "The Fresh Prince of Bel-Air." She has also appeared in "The X-Files," "Dexter," "Two and a Half Men," and more.
Mark Harelik as Dr. Eric Gablehauser – Then
It probably sucks if your boss dates your mom, and that’s exactly what happened to Sheldon Cooper. Dr. Eric Gablehauser is the boss of the Physics Department at Caltech, and Leonard, Raj, and Sheldon report to him.
While he does his work professionally and is respectful towards his patients, Sheldon doesn’t like him. Dr. Eric Gablehauser has appeared in seasons 1 and 2 of "The Big Bang Theory."
Mark Harelik as Dr. Eric Gablehauser – Now
Like many of the actors and actresses on this list, Mark Harelik dibbled and dabbled in multiple areas of the acting world. Not only is he an actor, but he’s also a playwright.
Mark has had a long and successful career, acting in major movies and television series, including "Jurassic Park III," in the legendary "Seinfeld," in the epic "Breaking Bad," "Prison Break" (intense), "Battle of the Sexes" (hilarious), just to name some. We look forward to seeing him in his next role.
Kate Micucci as Lucy – Then
Lucy is a very socially awkward and anxious woman who Raj meets at a singles-only Valentine’s Day party at the comic store.
She and Raj develop a romance in season 6, but Lucy eventually ends the relationship through a text message after Raj tries to convince Lucy to meet his friends. She says that he took things too far, and she doesn’t want to continue in the relationship.
Kate Micucci as Lucy – Now
Kate Micucci has worked as a voice actress in several animated series and films since she appeared in 8 episodes of TBBT. She was the voice of Irma Langinstein in Nickelodeon’s "Teenage Mutant Ninja Turtles" and Velma Dinkley in "Be Cool, Scooby-Doo."
She also was the voice of Webbigail in the Disney cartoon "DuckTales" and Sara Murphy in another Disney show titled "Milo Murphy’s Law." In 2017, the 37-year-old was the voice of Clayface in the "Lego Batman Movie."
April Bowlby as Rebecca – Then
Rebecca is the stunning blonde girlfriend of Caltech employee Bert. She became a personal trainer after she failed to make it as an actress.
The gang is pretty surprised that such a beautiful girl is dating an awkward scientist. Sheldon believes that Rebecca is a golddigger. Bert turns up at the apartment and announces that he broke it off with Rebecca.
April Bowlby as Rebecca – Now
April has had several other gigs besides as Rebecca in TBBT. She also played Kandi, the sweet and dimwitted young wife of Alan in "Two and a Half Men." She acted as Stacey Barrett in the series "Drop Dead Diva" for five years.
April Bowlby has made several appearances in television movies such as "A Mother’s Crime" and "Love’s Last Resort." The biggest of her recent roles was her regular portrayal of Elasti-girl in the TV show "Doom Patrol."
Kaley Cuoco as Penny Hofstadter – Then
Penny is Sheldon and Leonard’s beautiful blonde neighbor who is introduced in the first season. She considers herself a professional actress, although her acting resume is very short.
Penny gets most of her money from waitressing at The Cheesecake Factory. She has been Leonard’s love interest since the first episode and the couple dated on and off throughout the seasons until they eventually got married in Vegas in season 9. She later took a break from being an actress and started to work at Bernadette’s pharmaceutical company instead.
Kaley Cuoco as Penny Hofstadter – Now
Kaley Cuoco had a major role in a sitcom before TBBT. Before starring as Penny, Kaley played the lead role of Bridget Hennessy in the sitcom "8 Simple Rules," co-starring with the late John Ritter.
Kaley, along with her costars Jim and John, is one of TV’s highest-paid comedy actors and made $900,000 per episode for her role as Penny. The actress has become a millionaire from her television work and went on to launch her own production company.
Melissa Rauch as Bernadette Wolowitz – Then
Bernadette is a former waitress at The Cheesecake Factory who has finished her Ph.D. in microbiology. She was introduced to us in the third season when Penny introduced her to Howard.
At first, the two weren’t able to find anything in common but then bonded over the fact that they both have overbearing mothers. In season 4, Howard proposes to her, and they get married in season 6. Later, the two have two kids — a daughter named Halley and a son named Neil.
Melissa Rauch as Bernadette Wolowitz – Now
Before her major role in TBBT, Melissa made some other television appearances. She played minor parts in "The Office" and "True Blood."
Melissa also acted in a few movies such as "The Bronze" in 2015 and "Are You Here" in 2013. The actress (along with Mayim) got a raise after she signed on for season 11 and 12 and started making a whopping $500,000 per episode.
Bob Newhart as Arthur Jeffries — Then
Arthur Jeffries was the host of the kids' science show, "Professor Proton." Sheldon and Leonard looked up to him as kids, and they later become involved with him in real life, much to their delight.
In season seven, Jeffries dies, but that doesn't mean he was off the show. He kept coming up for a few more appearances in Sheldon's dreams, usually looking a little disoriented and wearing a "Star Wars" costume.
Bob Newhart as Arthur Jeffries — Now
Bib Newhart needs no introduction, but we're going to brave one anyway. With his brilliant example of deadpan comedy, Newhart has been a legend for many decades now. He had his big break in 1960 with "The Button-Down Mind Of Bob Newhart," his album of comedic monologues, and went on to have one of the most prolific careers the comedy world has ever seen.
After his role in "The Big Bang Theory," Newhart went on to reprise his role as Professor Proton (though mostly as a voice-over) in "Young Sheldon," the prequel show, depicting Sheldon's life as a little kid.
Brian Posehn as Bert Kibbler — Then
Bert is another researcher from Caltech — a geologist who enjoys the occasional rock pun, as his profession requires. In season 7, Bert expresses some interest in Amy, who remains oblivious until told about it by her friends.
We wouldn't worry about Bert's fate, though. He later turns out as a pretty sweet guy with a pretty cool job, and he even gets a fancy research grant most of the gang can only dream of.
Brian Posehn as Bert Kibbler — Now
While mostly appearing in minor roles, Brian Posehn has loads of acting credits to his name. He first started acting in various small roles in the mid-90s and has been in the industry ever since. He's done film, TV, voice acting and has even produced and written for television.
Among his latest roles, you can find a recurring role in the TV show "Top Secret Videos" and the voice role of Sour Cream in the sophisticated cartoon, "Steven Universe."
Judd Hirsch as Alfred Hofstadter — Then
Although mentioned many times over the course of the show, Alfred Hofstadter, Leonard's father, appears in the flesh for no more than two episodes. Before that, all the things the viewers knew about him were bits of information told by Leonard's mother, Beverly, which didn't paint him in a very flattering light.
However, the two eventually get divorced, which benefits them both. In fact, at the end of season 9, he meets Mary, Sheldon's mother, and the two seem to have good chemistry, which leads to a prospect of an interesting relationship.
Judd Hirsch as Alfred Hofstadter — Now
Judd Hirsch's impressive acting career stretches all the way back to the early 1970s! He started with a couple of tiny, uncredited roles and steadily climbed the ranks until getting his most memorable role as Alex Reiger in the TV show "Taxi," which ran for more than 100 episodes.
TBBT was a drop in the bucket of acting credits this actor has under his belt. After the show ended, he never went off screen and kept appearing regularly n a multitude of TV productions, and has even lent his voice to the Netflix hit adult cartoon "Big Mouth."
Regina King as Janine Davis — Then
In a show where most characters are awkward and socially inept, it's nice to occasionally be reminded of a normal person's perspective. Janine Davis is another Caltech employee, but she isn't a scientist. She works at the university's HR department, which makes her one of the very few sane voices on the show.
Whenever one of the main gang's men unknowingly does something inappropriate, you can trust Janine to lay down the law and explain some basic human etiquette. We very much appreciate her service.
Regina King as Janine Davis — Now
With a name so regal, you can't help but bow down to Regina King. Her acting career started with a bang when she landed the role of Brenda Jenkin in "227" — a role she stuck with for 5 years and 110 episodes. Not bad for a first gig!
Since then, this talented actress has been a series regular in more shows than we can count. ("24," "Southland," and "American Crime," just to name a few.) After TBBT was over, King went on to star a Sister Night (aka Angela Abar) in the hit superhero ministries, "Watchmen."
Joshua Malina as President Siebert — Then
All rise! Oh, wait, he isn't that kind of president. Dr. Siebert is a physicist and the president of Caltech. He cares about funds and funding, and... that's about it.
We meet him in season 3 for the first time, and his performances pepper the show for the rest of the show. In the 12th and final season, however, we get a much bigger dose of him, mainly thanks to the fact that Sheldon's research is making progress and he's in line for Nobel Prize.
Joshua Malina as President Siebert — Now
Molina has been acting since the early 90s, mostly in minor roles, until he got his first big part as Jeremy Goodwin in "Sports Night." He did that for two years and went on to other projects, such as a series regular in "The West Wing" and "Scandal."
After TBBT, Malina was only cast in small TV roles, but we have no doubt we will see him doing something pretty big pretty soon.