Based on a real incident between this film's screenwriter Robert Dozier and his father William Dozier, then head of production at RKO.
James MacArthur reprised his role as Hal Ditmer from the original television production Deal a Blow (1955).
First feature film directed by John Frankenheimer. He had worked in television prior to this. He reportedly did not like the experience and would not return to feature films until The Young Savages (1961).
This film's cast includes three actors who had prominently played apes in the early entries of the original saga that started with Planet of the Apes (1968)--Kim Hunter who played chimpanzee Dr. Zira in the first three films, James Daly who played orangutan Dr. Honorious in the original film, and James Gregory who played gorilla General Ursus in the second film Beneath the Planet of the Apes (1970). Also, the score of this movie was by Leonard Rosenman who would later compose the music for that second entry as well as the fifth one in the series, Battle for the Planet of the Apes (1973).