The actor originally cast as the architect who rings at the rich man's door did not show up, so Terrence Malick played the part himself. Malick later wanted to re-shoot the scene with another actor, but Martin Sheen refused to re-do the sequence with anyone else.
Charlie Sheen and Emilio Estevez's (Martin Sheen's sons) feature-film debut. Uncredited, both play boys under a lamppost.
Of the film's two lead stars, actress Sissy Spacek was cast first before actor Martin Sheen came on board, with Sheen first perceived as being too old for the character he would portray.
Sissy Spacek later said that working with Terrence Malick completely changed her whole attitude to film-making. She believes she would have had a much different career if she and Malick hadn't crossed paths.
The film's tag line ("In 1959 a lot of people were killing time. Kit and Holly were killing people.") inspired the Zodiac Killer, who had been lying low for years, to write a letter to a newspaper denouncing their flippant attitude to violence in society by running such an ad.
Terrence Malick: Uncredited, as an architect calling at a rich man's house in a scene with Kit (Martin Sheen).