These actors have CBS to thank for their popularity and their paychecks, not to mention quite a few Emmys among them. Check out The Big Bang Theory cast before they were stars!
After she was Bridget Hennessy on 8 Simple Rules, Kaley Cuoco did a stint as a witch-in-training on Charmed. Then she bought some boobs and moved in next to Leonard and Sheldon to set up residence as Penny on TBBT.
Prior to becoming Sheldon Cooper, Jim Parsons appeared in Zach Braff's Garden State and on Judging Amy.
Once upon a time, Johnny Galecki played Roseanne Conner's son-in-law on Roseanne after knocking up and marrying Darlene. Now he has Golden Globe and Emmy noms under his belt as Leonard on TBBT.
Kunal Nayyar had just two credits to his name prior to appearing on TBBT. One, a role on S.C.I.E.N.C.E, and another a guest spot on NCIS.
Simon Helberg's pre-TBBT credits include National Lampoon's Van Wilder and A Cinderella Story. Now he's a Critic's Choice Award winner for Best Supporting Actor.
After playing Blossom for five seasons, Mayim Bialik went to Yale and earned a Ph.D in Neuroscience. Now she plays Amy Farrah Fowler, a character not terribly unlike herself.
Standup comedian Melissa Rauch was little known in the acting world prior to becoming Bernadette and marrying Simon Helberg's Howard on TBBT.
Sara Gilbert, aka "DARLEEEEEEENE" on Roseanne, joined TBBT for only 8 episodes. During those episodes, she played the love interest of Johnny Galecki's Leonard, making this the second time the two have been romantically involved on-screen.
Kevin Sussman plays the friendly neighborhood comic book store owner Stuart Bloom. He once played America Ferrera's boyfriend Walter on Ugly Betty.