Although played by Paul Stevens, the character of Frank Wayne was dubbed by Martin Landau (Rollin Hand) so that Hand's transformation into Wayne would seem more credible. It was obviously Landau's voice speaking Frank's lines.
This episode marks the first use of new dossier pictures for Cinnamon, Rollin, and Barney.
"The Council" (parts 1 & 2 combined) was released in France in 1971 under the title "Mission impossible".
Phelps and Collier arrive at Frank Wayne's house in a black 1957 Ford Fairlane that bears the license plate NPH-623. The same license plate was sometimes seen on the "Monkeemobile" (a customized red Pontiac GTO) in The Monkees (1965)
Robert Phillips was a friend of the writers of this show, and the part of Johnny was written especially for him. In real life, Phillips was an undercover police officer and his career was the basis for 1959-60 television series "Tightrope".