Composer Jack Nitzsche who previously worked with Carpenter on Starman was the first choice of composer but he was unavailable. Producer Chevy Chase remembered seeing Shirley Walker conducting the orchestra when he was attending the scoring stage to his film Christmas Vacation so he suggested that they use Walker to score this film.
William Goldman originally wrote several drafts of the screenplay, all of which were rejected, as he wrote it as a simple comedy, and the producers preferred to use the film to "explore the loneliness of invisibility". Eventually, he left the project, though he still receives a screenplay credit. He claims never to have seen the movie, and thus cannot say for sure how much of his material is actually in the film.
When the Alice Monroe character is introduced, it is mentioned she has just returned from Brazil. Daryl Hannah's previous film to this one was At Play in the Fields of the Lord, filmed in Brazil.
This was John Carpenter's first film during the 1990s and also his first major studio film since Big Trouble in Little China. The reason he'd had not done one was due to the fact that he'd received a lot of studio interference on that film and felt restrained to do the films would've liked independently. Prince of Darkness and They Live were made during that time independently.
Ivan Reitman was originally set to direct the film, but when he and Chevy Chase couldn't agree on the tone, Reitman demanded the studio choose either he or Chase. They chose Chase.