Johnny Galecki

Johnny Galecki (born April 30, 1975) is an American actor and producer best known for portraying physicist Leonard Hofstadter on the CBS sitcom *The Big Bang Theory* (2007–2019). He began acting as a child and gained wide recognition as David Healy on the ABC sitcom *Roseanne* (1992–1997), a role he later reprised on *The Conners*. Galecki has also appeared in films including *National Lampoon’s Christmas Vacation* (1989) and *I Know What You Did Last Summer* (1997). For *The Big Bang Theory*, he received multiple Emmy Award nominations and served as a producer.