Otto Preminger became so fascinated with his son Erik Lee Preminger's description of life as a dropout in New York's Greenwich Village that when a mere writing sample from Doran William Cannon passed his desk, Preminger wanted to shoot the writing sample as opposed to the actual script, because the sample explored the hippie existence and LSD-tripping.

Otto Preminger experimented with LSD to prepare for this film. It is rumored that Groucho Marx also experimented with Timothy Leary.

Otto Preminger originally wanted Bob Dylan to score the movie. He invited Dylan and his wife to a screening of a rough cut of the movie in Preminger's Hollywood mansion. After the screening Dylan surprised everybody from his entourage, who thought the film was a disaster, by requesting a second screening but at one condition: he wanted to be left alone with his wife in the house during it. Preminger happily obliged, convinced that Dylan would accept the job. However, Dylan showed no further interest in the movie. He acknowledged later that he and his wife weren't interested at all by the film but they loved the mansion's style so much that they requested this second screening to freely explore it, write down what they liked and take inspiration for their own house.

Groucho Marx's LSD trip is the subject of the article "My Acid Trip with Groucho" by Paul Krassner, Yippie founder and editor/publisher of famed satirical magazine The Realist.

Faye Dunaway, under contract to Otto Preminger at the time, refused to appear in the film after her unexpected success in Bonnie and Clyde and was promptly sued by Preminger. The matter was settled out of court.

Cast members Burgess Meredith, Frank Gorshin, Cesar Romero and director Otto Preminger all appeared playing villains on the TV series Batman. Arnold Stang also appeared on the show uncredited in one episode.

Even though Groucho Marx was 78 years old and well past his Marx Bros. prime, Otto Preminger browbeat Groucho into wearing his old greasepaint-mustache get-up for the movie. He also berated Groucho on the set, causing his co-star Jackie Gleason to physically threaten Preminger to never try the same bullying behavior with him.

Final film of Groucho Marx.

God's yacht in the film was actually borrowed from John Wayne. Director Otto Preminger had directed Wayne in In Harm's Way and Wayne donated the yacht for use in the film.

In the film's TV-viewing opening, Otto Preminger's film In Harm's Way is featured. Preminger always complained about having his films cut to pieces on TV. Thus, Carol Channing's character says, "No, I never watch films on TV . . . they always cut them to pieces."

Several writers were brought in to "fix" this while Otto Preminger was shooting Doran William Cannon's original script. These "rescue writers" included Elliott Baker and Stanley Ralph Ross. By the time Ross was called in, the picture was nearly half done and the scenes that Ross suggested be cut had already been shot and roughly edited. Preminger never cheated on wages and paid Ross, Baker and several other writers in a vain attempt to add jokes. However, Preminger steadfastly refused to alter the structure of the story.

Towards the end, when George Raft marries Frankie Avalon and Donyale Luna, Raft's wedding-service manual is clearly seen as "The Death of God".