who played leonard in the big bang theory
Johnny Galecki John Mark Galecki (born April 30, 1975)[1] is an American actor. He is known for playing Leonard Hofstadter in the CBS sitcom The Big Bang Theory since 2007 and David Healy in the ABC sitcom Roseanne from 1992 to 1997. In 2018, he appeared in the revival of the sitcom reprising his role as David. Galecki also appeared in the films National Lampoon's Christmas Vacation (1989), Prancer (1989), Suicide Kings (1997), I Know What You Did Last Summer (1997), Bookies (2003), In Time (2011), and Rings (2017).