Johnny Galecki started acting when he was a child ... on many episodes of Roseanne when he was a teenager as the younger brother of Glenn Quinn’s character Mark Healy. He stayed on the show ...

Johnny Galecki wasn’t content to wait on an acting ... Galecki plays smartypants Rusty, the youngest brother to sassy Audrey (Juliette Lewis). In 1993, Galecki first appeared playing David ...

Also Read: Watch Johnny Galecki's Return to 'Roseanne' With Surprising News of David's Future (Video) Gilbert then said that she thought of the name Mark, because David’s brother, played by ...

Has “The Conners” said goodbye to Johnny Galecki’s David for good? It’s quite possible. David (Galecki) was revealed as an absentee dad to Harris (Emma Kenney) and her brother Mark (Ames ...