Johnny Galecki as Leonard Hofstadter From CBS Comedy 'The Big Bang Theory'

On the CBS comedy The Big Bang Theory, Johnny Galecki plays Leonard Hofstadter, an experimental physicist and the best friend and roommate of fellow scientist Sheldon Cooper. Like Sheldon, Leonard is socially awkward and geeky, but he handles interactions with other people much more capably than Sheldon does, and for a while he even dated Penny, the beautiful woman who lives across the hall from Leonard and Sheldon.