The movie is loosely based on the 1959 science fiction novel Immortality, Inc. by Robert Sheckley.
According to reports at the time of the production and interviews with some members of cast and crew, the original version of the movie had a disastrous test screening, so Producer Ronald Shusett was brought in to re-shoot around forty percent of the movie, and add more character scenes and humor. Emilio Estevez also mentioned how Director Geoff Murphy let them down by focusing too much on action, in his original cut of the film.
Linda Fiorentino was originally cast as Julie, but was replaced by Rene Russo after a week of shooting.
On VHS copies of the film, the music video for Scorpions "Hit between the Eyes" is included. The video contains concert footage and scenes from the movie.
Rene Russo met her husband, co-writer Dan Gilroy, during production. They have been married since 1992.
In the note on Albert Einstein's picture in the diner is a quote, "Imagination is more Important than Knowledge" attributed to Kia Ora. "Kia ora" is actually a phrase used as an informal greeting in the language of New Zealand's Maori people. Geoff Murphy was born in New Zealand and in this particular instance, most Maori people would regard the greeting as very tongue-in-cheek.
Vincent Schiavelli was slated to play an unscrupulous "insurance salesman", who sold life insurance policies to Freejacks.
Poor test screenings and subsequent re-shoots bumped it from its original fall 1991 release date.
As lead singer of the New York Dolls in the 1970s, David Johansen was often seen as a Trash rock version of Mick Jagger.
Emilio Estevez plays a race car driver. His brother, Charlie Sheen, previously starred in The Wraith (1986), a science fiction movie set against the backdrop of drag racing.