Galecki also appeared 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 until its finale in 1997.

It starred Jim Parsons, Kaley Cuoco, Johnny Galecki, Simon Helberg, Kunal Nayyar, Mayim Bialik and Melissa Rauch as […] ...

While Johnny Galecki has mostly lived a private life following the end of "The Big Bang ... Evelena joins big brother Orbison, whom Galecki welcomed with his ex Alaina Meyer in November 2019 ...

And then I said, ‘Oh, maybe Mark,’ because Mark was played by Glenn Quinn who was [Galecki’s] brother on the show who passed away.” Roseanne airs Tuesday (8 p.m. ET) on ABC. Close ...