The film was originally entitled Truth, Justice, and the American Way (after Superman's famous catchphrase). However, DC Comics (which owns the rights to the Superman character) refused to allow that. It also did not allow the Superman "S" insignia to be used in any of the trailers or promotional material of the film, but oddly enough allowed it to be in the actual movie.
The Alvis automobile George Reeves is shown washing in the film is an extremely rare model that was shipped to the location for use in the movie, as it is one of the few existing examples of the car Reeves actually owned.
The film's producers were forced to shoot a new version of the opening credits of the TV Adventures of Superman (1952) when Warner Bros. refused permission for the actual opening credits to be used within the film.
Joaquin Phoenix auditioned for the role of Louis Simo, but Adrien Brody got it. This is the second time the two have auditioned for the same role. In The Village (2004), both men auditioned for the role of Lucius Hunt, with Phoenix getting the role.
In the film, George Reeves is shown to have been injured while filming a takeoff from a garbage-strewn alley, a sequence that was used repeatedly in early episodes of the TV series. In reality, Reeves was injured while filming a takeoff for Adventures of Superman: Ghost Wolf (1953). He fell about 12 feet to the stage floor, landing on his back, when the rigging gave way.
George Reeves's agent, Gus Dembling, was combined in the film with the character of Reeves's manager, Arthur Weissman, who in actuality did not come into Reeves' life until much later than the film depicts.
The script George Reeves reads from at his audition is not from the Superman series. It features a villain named Prince, who did not appear in any episode, and his dialogue contains the word "superhero," which was never used in the series.