Belgian-born actor Johnny Galecki came to prominence on television under the overwhelming shadow of comedienne Roseanne Barr, only to reinvent himself years later as one of the stars of another wildly successful sitcom. After early roles in films like "A Night in the Life of Jimmy Reardon" (1988) and "National Lampoon's Christmas Vacation" (1989), the talented teen actor gained nationwide recognition as David Healy, boyfriend to the Conner's cynical daughter, Darlene (Sara Gilbert), on the sitcom phenomenon, "Roseanne" (ABC, 1988-1997). Determined not to suffer the fate endured by so many teen TV stars, Galecki continued to hone his craft after "Roseanne" ended, taking on roles in such indie films as "Suicide Kings" (1997) and "The Opposite of Sex" (1998), in addition to several critically lauded endeavors in live theater. A decade later, he returned triumphant to weekly television when he was cast as loveable geek Dr. Leonard Hofstadter on the smash hit sitcom "The Big Bang Theory" (CBS, 2007- ), co-starring newcomers Jim Parsons and Kaley Cuoco. An intelligent performer who made equally thoughtful career choices, Galecki's patience and perseverance paid off handsomely.