For release in Australia, the U.S. tagline "Get ready to root for the bad guy" was changed to "Get ready to cheer for the bad guy" because, as Mel Gibson himself pointed out, in Australia "to root" is slang for "to have sexual intercourse".
Director Brian Helgeland was fired from the film two days after he'd won his Academy Award for L.A. Confidential (1997).
Helgeland was in post-production on this film the night of the Academy Awards, and having been nominated for his L.A. Confidential (1997) script he really hoped he would be named the winner. "I knew that they were getting close to finally removing me off this movie," and he thought winning the Oscar would mean they couldn't fire him. He won, Sean Connery tousled his hair backstage while congratulating him, and that was his Sunday night. "And on Tuesday I got fired. So much for the magic of an Academy Award."
Brian Helgeland was working on the script for this film, in friend and mentor Richard Donner's office, on the Warner Brothers lot during post-production on their previous collaboration, Conspiracy Theory (1997). One day, Helgeland had gathered his script pages, and was on his way home, when Donner asked if he could go to the ADR stage, where he was scheduled to have a session with Mel Gibson, and inform him that he would be late. When Helgeland arrived at the stage, Gibson inquired about the script pages under his arm. After reading the first act, Gibson expressed interest in the project, but Helgeland informed him that he really wanted to direct it. Gibson offered that if he liked the finished script, he would give him a shot. Upon completion, Helgeland sent Gibson the script, expecting him to pass. After a couple of weeks, Gibson called and asked, "Can you be ready to shoot in twelve weeks?"
According to the director commentary, James Coburn found the prop cigars his character was supposed to use unfit for smoking. So, he went into Mel Gibson's trailer (Gibson wasn't there, as he wasn't scheduled for shooting at that moment) and helped himself to a few of Gibson's cigars.