In 1967, McMahon had a role in the film "The Incident" and appeared as Santa Claus on "The Mitzi Gaynor Christmas Show". From 1965 to 1969, McMahon served as "communicator" (host) of the Saturday afternoon segment of "Monitor", the weekend news, features and entertainment magazine on the NBC Radio Network. The 1955 movie "Dementia", which has music without dialogue, was released as "Daughter of Horror" in 1970. The newer version, which had a voice over by McMahon, still has music without dialogue, but with an added narration read by him. McMahon had a supporting role in the original "Fun with Dick and Jane" in 1977.