Johnny Galecki
John Mark Galecki is an American actor. He played Leonard Hofstadter in the CBS sitcom The Big Bang Theory and David Healy in the ABC sitcoms Roseanne and The Conners. Galecki also appeared in the films National Lampoon’s Christmas Vacation, Prancer, Suicide Kings, I Know What You Did Last Summer, Bookies, In Time, and Rings. In 2018, he was estimated...