Johnny Galecki

Before starring in "The Big Bang Theory," Johnny Galecki was best known to television audiences for his role as David in the long-running comedy series "Roseanne," for which he won a Young Artist Award. His other television series credits also include a recurring role in "My Boys" and guest appearances in "My Name is Earl." Galecki's feature film credits include "Hancock," opposite Will Smith, Charlize Theron and Jason Bateman, "Crystal," "Bookies," "Vanilla Sky," "Bounce," "Playing Mona Lisa," "The Opposite of Sex," "I Know What You Did Last Summer," "Suicide Kings" and "National Lampoon's Christmas Vacation."

He starred in the Tony Award-nominated Broadway play "The Little Dog Laughed," for which he received a 2007 Theatre World Award for outstanding Broadway debut. His other theater credits include "The Drawer Boy" and "Pot Mom," at Chicago's Steppenwolf Theatre, "The Member of the Wedding," for which he was nominated for a Joseph Jefferson Award, and "Galileo," at Chicago's Goodman Theatre. Galecki was born in Belgium where his father was stationed while serving in the U.S. Air Force. He was raised in Chicago, Ill., and currently lives in New York. His birth date is April 30.