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: 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.