Did You Know?

In Dennis Lehane's novel, the surname of the characters of Jimmy and his family is Marcus, however in the film, it is Markum.

More than 2,000 people who wanted to be extras in the movie showed up at the Boston Teachers Union on 14 September 2002 for the open casting call. Carolyn Pickman of Collinge-Pickman Casting told The Boston Globe a week later that about two-thirds of those trying out would be called to fill a church and a local bar, play spectators at a parade, or walk through other scenes. All types of people from the greater Boston area (and as far away as New Hampshire) attended the call, where they waited in long lines to eventually hand in their applications and get their pictures taken.

Clint Eastwood narrated the teaser trailer.

The situation at the opening of the movie is based on an incident when, as a child, author Dennis Lehane's mother castigated him for getting into a car with men who claimed to be plainclothes policemen.

Michael Keaton was originally cast as Sean Devine. He had done several script readings with the rest of the principal cast, and he had been doing research for the role with the Massachusetts State Police Department, and living in Boston for several weeks. A month before principal photography was to start, Keaton and director Clint Eastwood got into a huge argument, and Keaton left the project. A week later, Kevin Bacon was cast in the role.

The tune that the band is playing during the parade at the end of the movie is John Philip Sousa's "Semper Fidelis", which is Latin for "always faithful".

The studio executives at Warner Brothers wanted Clint Eastwood to shoot the film in Toronto, Canada to save money. Eastwood refused and pushed to have the film completely shot in Boston where the film is set.

In Sean Penn and Tim Robbins's only previous feature together - Dead Man Walking - both were respectively Oscar-nominated as Best Actor and Best Director. On this one, both were victorious as actors.

Dennis Lehane:  author of the novel can be seen waving from the back of a convertible in the parade sequence.

For the scene where Jimmy wails and thrashes in anguish at the discovery of Katie's body, Sean Penn requested that a tank of oxygen be standing by after he finished the take.