Originally the film was a more special-effects oriented, blockbuster-type movie and was turned down by Al Pacino five times. But when Taylor Hackford went through a few script re-writes he offered it to Pacino again. Pacino liked it, but didn't think he could portray Milton properly, and suggested Sean Connery or Robert Redford instead.
Each time Mary Ann (Charlize Theron) tries a different color of green on the apartment walls, only to be discouraged by her "friend" Jackie (Tamara Tunie), Jackie is wearing some article of clothing or jewelry that is the exact same shade of green.
The boxing match that Lomax and Milton attend was not a staged bout, but in fact a legitimate world championship boxing match. The bout occurred on October 4, 1996, at Madison Square Garden in New York City. Roy Jones Jr., IBF super-middleweight champion, squared off against top contender Bryant Brannon. Jones knocked out Brannon during the second round of the bout.
The character of John Milton is named for John Milton, the author of "Paradise Lost," the classic epic poem about man's fall from God's grace. When Lomax is in Milton's office at the end of the film, he says "Better to reign in Hell than serve in Heaven," from Book I Line 263 of the same work.
The outdoor patio in John Milton's office actually was on the 50th floor of a New York building. The actual stage was 8ft away from the edge of the building. Thus what one would imagine is a bluescreen shot is actually real.
Sculptor Frederick Hart and the Episcopal National Cathedral in Washington, DC, sued Warner Brothers over a sculpture that appears in the film and closely resembles Hart's "Ex Nihilo", which is situated above Milton's desk in his apartment. A last-minute deal was negotiated to allow the sculpture to remain in the film.
The character Kevin Lomax's name may be a reference to being a "Low MACH." This is a term used to describe those people scoring below 60/100 on the MACH-IV test used by personality and social psychologists to measure "Machiavellianism" which is a measure of a person's tendency to manipulate and deceive others for personal gain. E.g. "Low MACHs" tend to agree with the following statements (taken from the test): No. 7.) "There is no excuse for lying to someone else." No. 11.) "Most people who get ahead in the world lead clean, moral lives." These are precisely some of the personal moral issues faced by the character in the film.
Lomax and Milton run into Don King at the bout. King was in attendance that night because one of the fighters he promoted at the time, Oba Carr, fought on the undercard of the Roy Jones Jr.-Bryant Brannon bout. Carr lost a 12-round decision to WBA welterweight champion Ike Quartey.
At the end of the movie Keanu Reeves appears moving by an totally empty New York City's Fifth Avenue, without cars or people. This scene was victim of a certain polemic due to Open Your Eyes (1997), where its main actor, Eduardo Noriega, appears in a too empty Madrid's Gran Vía, creating a doubt about which of the two scenes was copied (or plagiarized) of the other.