Trivia: The infant playing Connie and Carlo's baby son Michael Francis Rizzi who Kay holds during the christening scene is Sofia Coppola, Francis Ford Coppola's daughter, who was born in May 1971. Sofia later had a prominent role in Part III as Michael's daughter, Mary. Other than the main characters, Sofia is the only actor to have appeared in all three films. In The Godfather II, she can be briefly seen as an immigrant girl on the ship that brings Vito Corleone to Ellis Island.
Trivia: At the end of the film, the police officer advising Beatty and Voight to go away and not to come back is James Dickey, the screenwriter and author of the book the film is based on.
Trivia: The scene where Belle (Shelly Winters) dives into the water was actually rehearsed by having her jump into the water. She decided to dive in while filming the scene and that take was used.
Trivia: Marguerite Wyke was "played" by Joanne Woodward, the wife of Paul Newman. Woodward's likeness was used for Andrew's painting of Marguerite, and the actress listed as playing her was a fictional name.
Trivia: When Jason dies at the end of the film, it is not Ray Milland you see but a double. This is due to the fact that Milland quit the film three days early due to his intense hatred of the production.
Trivia: Hitchcock's cameo can be seen three minutes into the film, just after the opening credits. As Sir George espouses the virtues of a clean river, Hitchcock can be seen in the crowd wearing a bowler hat.
Trivia: Sissy Spacek as Poppy never once wears the outfit she's shown wearing on the DVD box art. This is either a publicity still or it came from another movie of hers, The Badlands.