At the time of his death in November 2007, he was the only surviving member of either the cast or crew of Citizen Kane (1941). He portrayed Charles Foster Kane III, the title character's son. Coincidentally, his elder sister Ann Bupp was one of the last surviving cast members of Gone with the Wind (1939).
Interviewed in "Growing Up on the Set: Interviews with 39 Former Child Actors of Classic Film and Television" by Tom Goldrup and Jim Goldrup (McFarland, 2002).