Johnny Galecki is one of those television stars who has quietly managed to be super successful without a lot of fanfare. He launched his career at the tender age of twelve with the film, Time Out for Dad. But his first really big role was the part of troubled teen, David Healy, on the sitcom, Roseanne. He continued to appear in films, including Prancer, Suicide Kings, I Know What You Did Last Summer, Bookies, and Rings, amongst others.
Though he is well suited to both the big and small screens, Galecki is definitely a TV man at heart. These days, he is best known for playing Leonard Hofstadter on sitcom, The Big Bang Theory. He has been working on the show since 2007 and now commands a whopping $900,000 per episode. If that's not acting success, we don't know what is!