Filming did not take place in Arlington Heights, Illinois (a suburb of Chicago) because the weather was too cold.
Released to DVD just nine weeks after it opened in theaters.
The production was shot without a completed script. As a result, there were many delays and arguments over what to shoot. Actor James Gandolfini admitted in behind the scenes interview that most of the film was "improvised".
The original Christmas 2003 release date was pushed back ten months, to avoid competing with another Ben Affleck film, Paycheck (2003). Because of this, there's a 2003 calendar hanging in Brian's bedroom, near the door.
Jon Favreau was offered a chance to direct, but made Elf (2003) instead.
James Gandolfini was only 10 years older than Christina Applegate, who plays his daughter in the film.