Claim: Johnny Galecki played an uneducated character in The Big Bang Theory.
Evidence: He is known for playing David Healy in the ABC sitcom Roseanne from 1992 -- 1997 and Dr. Leonard Hofstadter in the CBS sitcom The Big Bang Theory since 2007.
Leonard is an experimental physicist , who shares an apartment with colleague and best friend Dr. Sheldon Cooper -LRB- Jim Parsons -RRB-.