Jacques Tourneur never planned to show the monster but to leave it instead to the audience's imagination. However, the studio insisted that the monster be shown and added it in post-production, allegedly without Tourneur's consent, approval, or involvement.
"The scenes where we really see the demon were shot without me. All except one: I shot the sequence in the woods where Andrews is pursued by this sort of cloud." [Tourneur himself in Midi-Minuit Fantastique 5.65]. He also said, "It should have been unveiled bit by bit without it ever really being shown." [in Cinefantsatique; '73]
Dana Andrews was so impressed with director Jacques Tourneur that when he returned to the United States, he had Tourneur direct his next film, The Fearmakers (1958).
Charles Bennett was angry at the changes made to his script by producer Hal E. Chester. In an interview, Bennett said, "If [Chester] walked up my driveway right now, I'd shoot him dead."
Ray Harryhausen was contacted to create the effect scenes with the demon, but he was already committed to his project The 7th Voyage of Sinbad (1958) with producer Charles H. Schneer.
Before its release in the U.S., this film was retitled from "Night of the Demon" to "Curse of the Demon" and cut from 95 to 82 minutes. It was shown as the lower half of a double bill with Hammer Films' The Revenge of Frankenstein (1958) or The True Story of Lynn Stuart (1958).