* BannedInChina: Because it was potentially offensive to [[spoiler: Christians]], the original South African cut dropped the final scene.
* DoingItForTheArt: Beyond the effort he made to get the movie off the ground in the first place, Creator/PeterSellers gained weight to play Chance despite chronic and worsening heart problems -- and he hated how he looked this way -- solely because he thought Chance would be overweight given his sedentary lifestyle. He lost the weight as fast as he could after filming, which may or may not have been a contributing factor to his death.
* DyeingForYourArt: Almost averted. Sellers let his gray hair show, unlike in most of his later films, but he did have it cut.
* FakeAmerican: Peter Sellers, a Brit, as Chance. In the film, Chance lives in Washington, D.C., but Sellers intentionally plays him without any kind of specific regional dialect/accent as per a description in the book. To pull this off, Sellers took (British) Stan Laurel's voice and gave it a generic "American" accent. Sellers was a huge fan of Laurel and Hardy and openly admitted to using Laurel's screen persona to inform his performance as Chance, which makes this a big ShoutOut of sorts.
* HeyItsThatGuy: One of the President's aides is Gov. Gatling from ''{{Benson}}''.
** If Sally the lawyer's voice sounds vaguely familiar, that's because she's played by Fran Brill, aka [[SesameStreet Prairie Dawn and Zoe]].
* {{Lzherusskie}}: Richard Basehart, an American, as the Russian ambassador.
* PlayingAgainstType: Sellers had such range that saying he had one type isn't accurate, but audiences knew him best as LargeHam FunnyForeigner [[Franchise/ThePinkPanther Inspector Clouseau]] by 1979 due to the role dominating his career comeback. This ''much'' more serene character and story certainly was a change of pace.
* RealitySubtext: Sellers never hid his motivations for wanting to play Chance. He even had business cards made up with Chance's name in place of his own, and was known to occasionally confuse people by suddenly assuming Chance's persona -- and this was ''before'' the film was greenlit.
* SavedFromDevelopmentHell: It took a long time getting the rights from Kosinski (he wanted to make a film version on his own; he did co-write the film that was made), as well as getting financial backing.
* UnintentionalPeriodPiece: For the end of TheSeventies via the fashions and all the authentic TV footage used.
* WhatCouldHaveBeen
** Solely because of the "I like to watch" scene, LaurenceOlivier turned down the role of Ben Rand, the role which Melvyn Douglas won a Supporting Actor Oscar for.
** At one point in the mid-'70s, it was announced that Gore Vidal was going to write the screenplay.
** The filming script's ending was significantly different than what was ultimately conceived and used. [[spoiler: Eve follows Chance after he wanders away and they head back together. He leaves his umbrella behind to shield a small tree -- that would have been the highly symbolic final shot.]] This ending ''was'' shot, and a publicity still from the press kit was drawn from it, but the actual scene didn't surface until the 2009 Blu-Ray disc.