Leonard Hofstadter is a character from the popular CBS television series The Big Bang Theory portrayed by Johnny Galecki. Hofstadter appears in "Business Guy" in an episode of The Big Bang Theory, with Galecki reprising his role. Categories: Family Guy Universe Independently Wealthy Perverts PHD The Big Bang Theory Real People Humans Male Genius Author Muggles Actors Heterosexuality Siblings Son Scientists Community content is available under CC-BY-SA unless otherwise noted.