Johnny Galecki. Actor: The Big Bang Theory. John Mark Galecki was born in Bree, Belgium, to American parents; his father was stationed there while serving in the U.S. Air Force. When he was three years old, his family moved to Chicago, Illinois, where he grew up with his parents, Mary Lou and Richard Galecki, and siblings, sister Allison (1980) and brother Nick (1982). His father was of Polish descent, and...