Johnny Galecki has appeared in just one American sitcom.
 In 1990, he was cast as Danny Nash, the son of Robert Urich's lead character, on the NBC comedy American Dreamer; the following season, he was a regular cast member on the ABC sitcom Billy, a spin-off from Head of the Class
 Galecki is the eldest of three children with a sister, Allison, and a brother, Nick, whom he describes as a "mechanical genius" in the automotive industry

