David (Newman/Kornman) is the younger brother of Mary Kornman in Good Cheer. She can be seen looking after him during Christmas 1925. He also appears in the audience for Mickey's movie filmed by Billy Lord's camera.
There are two other appearances of kids that resemble him. One is a rare appearance of a one-time younger brother for Mickey and/or Jackie Condon in Circus Fever; he also resembles the son of a woman who shares her berth with Mary during a train ride in The Big Town. (Most episodes place Greenpoint, the Rascals' hometown, in California, so this is one long train ride!)
David was played by actor David Durand.