Keye Luke first worked with David Janssen 18 years prior to this on an episode of Janssen's first TV show, "Chinese Honeymoon (1958)." Luke played a doctor and Janssen played a private detective.
Dean Jagger, who plays Simon Applequist here, went way back with David Janssen. They were costars in an episode of "There Were Four (1957)" and of "Right in the Middle of the Season (1966)."