Johnny Galecki was born in Bree, Belgium in 1975. His most famous role is that of Leonard Hofstadter on the TV serial, The Big Bang Click to look into! >> Read More... Theory. Johnny was born in Belgium due to his father being a member of the United States Air Force. Galecki has two younger siblings, Nick Galecki and Allison. Galecki said his parents were both very loving but very tough as well. Galecki’s acting debut came with the miniseries Murder Ordained. He then went on to play Rusty Griswold In National Lampoon’s Christmas Vacation. After this was one of his best known roles as Kevin Healy on the sitcom, Roseanne. He was also cast in the horror film, I Know What You Did Last Summer in 1997 as well as The Opposite Sex in 1998. In 2000, he starred in Bounce. Johnny also played minor roles in movies such as Suicide Kings and Vanilla Sky. He returned to TV for a short period by playing Trouty on the TBS show MY Boys. In 2007 Galecki took home a Theater World Award for his performance in The Little Dog Laughed. Johnny played a prostitute called Alex. Johnny Galecki currently stars as Leonard Hofstadter on the hit TV show The Big Bang Theory. Several co-stars from his time on Rosseanne also appear on The Big Bang Theory. He is reported to earn about 1 million dollars per episode.