Arnold Schwarzenegger's first film since Batman & Robin (1997). The reason for the gap was because of his heart surgery after playing Mr Freeze; the studios were anxious about whether or not they could insure him, and despite attempts to convince them he was in perfect health, he couldn't get any work until End of Days (1999). Even then, he was amazed when insurance people and executives from Universal came to the set just to watch him, to see if he was still up to the action scenes. They asked Schwarzenegger if he enjoyed this kind of punishment, but he said he was used to it. After the first week of shooting, the insurance guys backed off and not long after, the film offers started rolling in again.
Marcus Nispel quit the project not because of creative differences but because of embarrassment when a 64-page manifesto of his on-set demands was leaked to the press.
Arnold Schwarzenegger found the finished film too dark - not concerning the themes or story - but director and DOP Peter Hyams's lighting. For the same reason, this was the last movie that Steven Kemper edited for Hyams, as the dark lighting caused all kinds of editorial difficulties.
Udo Kier claimed in an interview that he was considered for the role of Satan in the film but the producers didn't want the hero and villain to both have German/Austrian accents, and he was eventually cast in a secondary role.
Father Kovak says to Jericho Cane that "Satan's greatest trick was convincing man he didn't exist". This quote from the French poet Charles Baudelaire also appears in The Usual Suspects (1995), also featuring Gabriel Byrne and Kevin Pollak.
Sven-Ole Thorsen: Arnold Schwarzenegger's friend and frequent collaborator appears as one of the thugs who breaks into Jericho's apartment.
Peter Hyams: [Spota] The name of the bar on the matchbook is Spota's. The name Spota appears as a character name in several other of Hyams' movies.