- Acting for Two: Christopher Reeve in the junkyard fight.
- B-Team Sequel: To the Richard Donner-helmed Superman and (more or less) Superman II.
- California Doubling: The movie was shot in Calgary and High River, Alberta. Calgary doubled for Metropolis, while High River doubled for Smallville. This continued the trend from the last two films. In fact, the opening to the film takes place in downtown Calgary, as you may notice from the buildings.
- Fake American: Most of the cast in this and the previous films consisted of mainly British actors, apart from the lead roles. Most of them assuming American accents to appeal to the Americanism of the film.
- Milestone Celebration: The film was released in the year of Superman's 45th anniversary.
- Money, Dear Boy: In his autobiography, Richard Pryor admitted that he thought the screenplay for this movie was terrible and he only accepted the role because he was offered $5 million for it.
- Old Shame: Christopher Reeve felt so ashamed about this movie that he swore he'd never play Superman again. It took lots of persuasion to bring him back for Superman IV: The Quest for Peace, which sadly didn't turn out much better.
- Promoted Fangirl: Annette O'Toole admitted in an interview for the documentary Look, Up in the Sky! that she loved reading Superman comics as a child, and preferred Lana Lang to Lois Lane.
- Refitted for Sequel: The scenes in which Superman straightens the leaning tower of Pisa and then leans it back in the end were originally planned for Superman II.
- Romance on the Set: Richard Pryor and Margot Kidder had an affair during filming.
- Technology Marches On: In one scene, a computer teachers says you can't do two things at once on a computer. Modern-day computers do multiple things at one time as a matter of course.
- Throw It In!: Reportedly, Richard Pryor was encouraged to ad-lib a lot, but because he was a Superman fan, he mostly stuck to the script.
- Troubled Production: This had perhaps the smoothest production phase of all the Christopher Reeve Superman films, but still had to suffer heavy re-writes after the original script featuring Brainiac and Supergirl was rejected, since it was considered too expensive to film because of its inferior budget compared to the previous two movies (plus, they wanted to give Supergirl her own movie). Christopher Reeve did not want to play Superman once again, partly because he was fed up with the role and partly because he felt that Richard Donner had been unfairly treated, leading the producers to scramble for replacements (Tony Danza was heavily considered for Reeves role). It was only when they allowed Reeve veto power over the script that they got him back. Apparently Lois Lanes role was reduced to five minutes after actress Margot Kidder publicly expressed some sympathy for Richard Donner after the Salkinds fired him. Taking Donner and Kidders side, Gene Hackman refused to return for this film. The video game that Ross Webster plays in the film was developed especially for the movie but had to be downgraded because the original version was considered too realistic for 1983. Richard Pryor was coked out of his brains during filming. On top of all that, a threatened lawsuit from the producers of Kramer vs. Kramer forced the originally-planned title, Superman vs. Superman: Superman III to be ditched, after the Salkinds decided it wasn't worth the fight.
- Unintentional Period Piece: Aside from the vintage computers in the office scenes, has a number of other very, very Eighties elements. Jimmy's hair manages to look both geeky at the time of release and Eighties today, the amount of money Gus steals via Penny Shaving would look like a routine clerical error in the 2010s, and a bunch of women at Gus's workplace are seen swapping their high heels for canvas running shoes in preparation for the walk home. It can even be pegged to the early end of the decade, because every older car is a 1970s model, while Gus's new Porsche screams '80s.
- What Could Have Been:
- According to Ilya Salkind, the original script was going to involve Brainiac and Mr. Mxyzptlk (who would have played by Dudley Moore) teaming up against Superman, who would also meet his cousin, Supergirl, who was adopted by Brainiac. The three characters would have been involved in a Love Triangle, with a jealous Brainiac turning Superman evil and Supergirl agreeing to marry him if he returned Superman to normal. Superman would have made a deal with Mxyzptlk to transport him and Brainiac to another dimension in order to settle the matter without superpowers, which they would have done by jousting in medieval armor.
- Alan Alda and Frank Langella were both considered for the role of Ross Webster. At least Frank got a role later.
- Jennifer Jason Leigh was originally set to star as Lana Lang, but turned down the role because she was too young.
- Gus Gorman was meant to be the human guise of Brainiac.
- Ross Webster and his mistress were likely intended to be Lex Luthor and Ms. Tessmacher.
- Christopher Reeve threatened not to return for this film in protest of the treatment of Richard Donner and also because he hated the script. With the film already in preproduction, the producers scrambled to find an actor to play Superman. John Travolta was approached but declined. Jeff Bridges and Kurt Russell were also considered but were also not interested. Finally with filming days away from beginning, the Salkinds settled on Tony Danza. Richard Lester was mortified with the casting of Danza and pleaded for Reeve to return. Reeve eventually agreed under the condition that he could make numerous changes to the script. The producers agreed and Reeve reprised his role.
- Working Title: Superman vs. Superman. The producers of Kramer vs. Kramer threatened a lawsuit, refusing to believe the Salkinds' explanation that it was intended as a play on various "Superman vs..." comic stories. Eventually Pierre Spengler suggested that Superman III would be a more sensible title anyway, and the issue was dropped.
- You Look Familiar: Pamela Mandell, who played Mrs. Stokis was also the diner waitress in Superman II.
Trivia / Superman III