The Big Bang Theory Cast

The Big Bang Theory cast is headlined by Johnny Galecki and Kaley Cuoco.

By Matthew Creith | Updated

The Big Bang Theory cast became an instant sitcom classic group when the show first aired on CBS in 2007. But hardly anyone could have predicted that the science-heavy dork comedy series would run for 12 seasons. Premiering at the height of network television’s glory, The Big Bang Theory was created by Chuck Lorre of Two and a Half Men and Roseanne fame along with writer Bill Prady. The show was such a success that it spawned a spin-off entitled Young Sheldon

The Big Bang Theory initially focused on the pathetic love lives of young physicists living in Pasadena, California, but added more cast members as the series grew in popularity.

In a proper “will-they-or-won’t-they” plot point, The Big Bang Theory started as a vehicle to showcase the unlikely romance between Johnny Galecki’s geeky character of Leonard Hofstadter, and Kaley Cuoco’s attractive newbie neighbor, Penny.

Striking a balance of romance and comedy elements, Jim Parsons became the series’ breakout star with his take on the stubborn and know-it-all character Sheldon Cooper.

The show went on to be critically acclaimed, with Rotten Tomatoes currently ranking The Big Bang Theory with 81% on its Tomatometer.


Johnny Galecki – Leonard Hofstadter

Coming straight off his Roseanne roots, actor Johnny Galecki got the chance to lead his own sitcom by starring as part of The Big Bang Theory cast as Leonard Hofstadter. Leonard lives with Sheldon Cooper, although the two are more roommates than close friends.

Bonded by their love of physics and their positions at the California Institute of Technology, the two men often talk to one another about comic books and science-fiction television shows.

Leonard has had his fair share of romance compared to his friends, Howard and Raj, but he meets his match in Penny, a wannabe actress who moves from Omaha to across Leonard and Sheldon’s hall. 

The Big Bang Theory initially centers on these five individuals, focusing mainly on Leonard and Penny’s on-again-off-again dating lives. Coming from an accomplished family, Leonard tends to be shy and has a lot of confidence-building to do throughout the series.

Kaley Cuoco – Penny

As opposed to her romantic interest Leonard, Penny is outgoing and street-smart beyond the boys in her life’s comprehension. Beautiful and funny, Penny is a struggling actress who moonlights as a server at the local Pasadena Cheesecake Factory, where her friends often dine. 

Kaley Cuoco embodies Penny as a central figure in The Big Bang Theory cast, where Sheldon often ridicules her for her simplistic small-town nature, even though she gets the better of him most of the time.

Jim Parsons – Sheldon Cooper

One of the most acclaimed actors to come out of The Big Bang Theory cast was noted stage performer Jim Parsons portraying Star Trek-loving Sheldon Cooper. A child prodigy turned socially awkward theoretical physicist, Sheldon is a Texas native who lives and breathes science and works hard to be the best in his field. He is also extremely impolite, egotistical, and immature for his age, with The Huffington Post remarking on the character’s ability to develop his own catchphrase: “Bazinga!”

For much of the early seasons of The Big Bang Theory, the cast of characters don’t generally like Sheldon’s crass nature, often tolerating him for being Leonard’s roommate and Sheldon’s appreciation for some of the “nerdy” media the others like as well.

As the series grew in popularity, the writers chose to give Sheldon a romantic interest in Amy Farrah Fowler, although the two don’t consummate their relationship for a long time. Parsons’ take on the character became so successful that he wound up winning the Primetime Emmy Award for Outstanding Lead Actor in a Comedy Series four times.

Simon Helberg – Howard Wolowitz

Continuing the trend of nerds going mainstream, Simon Helberg plays Howard Wolowitz, a Jewish aerospace engineer who still lives at home with his loud and obnoxious mother. As the only member of the gang that doesn’t have a doctorate, Howard often gets made fun of by Sheldon for his perceived failures.

Allergic to just about everything under the sun, Howard hides his insecurities by attempting to be a womanizer in the early seasons, which dwindles after he starts a romance with Bernadette Rostenkowski.

Kunal Nayyar – Raj Koothrappali

Unable to speak to women unless he is drunk, Kunal Nayyar is the last of the five original The Big Bang Theory cast members, portraying the Indian native Raj Koothrappali. Raj also works at CalTech, and while it is often speculated that he might be gay, he is a perpetually single straight man through much of the series. A romantic comedy movie aficionado, Raj is unlucky in love himself but lives vicariously through the experiences of his close friends.

Melissa Rauch – Bernadette Rostenkowski (Wolowitz)

Melissa Rauch joined The Big Bang Theory cast beginning in Season 2 as a server pal of Penny’s at the Cheesecake Factory, but she is also a graduate student working in microbiology. Bernadette and Howard start to date and eventually marry in the show, revealing other sides to her character as an innovative and competitive person.

Melissa Rauch conceived Bernadette’s signature voice for the show, and fans are often confused when they see her in interviews or other content using her natural voice.

Mayim Bialik – Amy Farrah Fowler

Blossom alum and future Jeopardy! host Mayim Bialik also joined The Big Bang Theory cast in later seasons, starting at the very end of Season 3 and remaining on the show until its conclusion in 2019. A television veteran and real-life Ph.D., Bialik plays Amy Farrah Fowler, a neuroscientist who works on addiction issues using primates.

As Sheldon’s sole love interest, Amy is just as intelligent and equally irritable as he is, although her infatuation with Penny and friendship with Bernadette creates a sisterly dynamic that was missing in earlier seasons of the show.


Kevin Sussman – Stuart Bloom

Comic book store owner Stuart Bloom is a regular part of The Big Bang Theory cast, as his store is the central location of many hangouts between the main characters. Sometimes unlucky in love like many of his customers, Stuart is regarded as a frail character who wears his heart on his sleeve.

But Sussman ends up getting a pretty happy conclusion by the end of the series, which caps off the character of Stuart nicely.

John Ross Bowie – Barry Kripke

the big bang theory cast

John Ross Bowie plays Barry Kripke, a coworker of the males of the series who tends to butt heads with Sheldon on a regular basis. Defined by his inability to pronounce his Rs and Ls, Kripke is otherwise a confident physicist.

Sara Gilbert – Leslie Winkle

the big bang theory cast

Another Roseanne staple who finds her way onto The Big Bang Theory cast, Sara Gilbert portrays Leslie Winkle on the television show. Leslie is a female version of Leonard, and the two date early in the series, much to the displeasure of Sheldon. Sheldon despises Leslie’s ideas on scientific matters in the lab, but the character frequently reappears in the early and later seasons of the show.

Laura Spencer – Emily Sweeney

the big bang theory cast

Later in The Big Bang Theory, it is clear that Raj is one of the only cast of characters to not find a stable relationship to call his own. Starting in Season 7, Laura Spencer is introduced as dermatology resident Emily Sweeney after Raj finds her on a dating website, and the two have a romantic entanglement that lasts for a short time. Emily clashes with other members of the gang at times and tends to enjoy macabre things.


Laurie Metcalf – Mary Cooper

Yet another Roseanne alum, Laurie Metcalf graces television screens by playing Mary Cooper as part of The Big Bang Theory cast, the mother of Sheldon, who visits from East Texas. A bible-loving, no-nonsense presence in Sheldon’s life, Mary is the complete opposite of Sheldon in almost every way, but he appreciates her nonetheless.

Her rendition of “Soft Kitty” for Sheldon whenever he is sick tends to make the grown man feel better instantly, and while he fights with her over her religious upbringing, she’s a caring nurturer in his life.

Christine Baranski – Beverly Hofstadter

the big bang theory cast

A theme of The Big Bang Theory, other than utilizing the star power from previous Chuck Lorre productions, is defining the cast of characters by their respective parental figures.

Christine Baranski plays Beverly Hofstadter throughout the series in various guest appearances as the accomplished mother of Leonard, who is just as cold as Sheldon without a spark of motherly love. Sheldon respects Beverly’s tenacity and genius, while Leonard feels humiliated whenever she visits.

Wil Wheaton as Himself

the big bang theory cast

Playing a fictionalized version of himself in many appearances in The Big Bang Theory, former Star Trek: The Next Generation actor Wil Wheaton crosses paths with the rest of the cast.

Once the epitome of Sheldon’s celebrity fondness, Wheaton disappointed the younger Sheldon when he didn’t turn up at a fan convention in the 1990s, and from then on out, Wheaton was seen as Sheldon’s mortal enemy.

While many other Star Trek alums show their faces on The Big Bang Theory, Wheaton evolves into a staple of the series.