Actor · DirectorJohnny GaleckiApril 30, 1975(49 years old)Bree, BelgiumJohnny Galecki is a Belgian-born American actor, best known for his roles as David Healy in Roseanne, Rusty Griswold in National Lampoon's Christmas Vacation, and as Leonard Hofstadter in The Big Bang Theory.SocialsInstagramTwitterIMDbKnown forThe Big Bang TheoryLeonard HofstadterNational Lampoon's Christmas VacationRussell 'Rusty' GriswoldIn TimeBorelRingsGabriel BrownFamily GuyLeonard Hofstadter (voice)HancockJeremyI Know What You Did Last SummerMax NeurickThe Opposite of SexJason BockVanilla SkyPeter BrownAmerican Dad!Arnie (voice)A Dog's JourneyHenry MontgomeryBeanStingo Wheelie