While it may be a "Mission Impossible" to determine what actor has appeared the most often in movies featured on MST3K, one good candidate is this man, who played "oveur" 70 roles in film and movies. MST3K viewers would have seen him as Paul Whitley in "SST: Death Flight", Dr. Paul Nelson in "It Conquered The World", an uncredited narrator in "Attack of the Eye Creatures", Ed Wainwright in "Beginning of the End", and Jeffrey Knight in "Parts: The Clonus Horror".
Peter Graves