The line "wouldn't hurt a fly" in the context of a police interrogation.
Sean Devine, played by Kevin Bacon, responds to the mention of Jimmy Markum as an accomplice of Just Ray Harris with the line "And the hits just keep on coming." This exact line was uttered by Tom Cruise in A Few Good Men (1992), in which Bacon played Cruise's friend and rival.
At the parade in the end, a kid is holding a SpongeBob SquarePants doll.
When Brendan Harris first comes into Jimmy's store, there is an issue of "People Magazine" with the CSI-cast on the cover, visible on the rack in the background.
The cast references the film and Sean Penn.
poster in store
Mentioned by Clint Eastwood.
Mentioned in a conversation
on shelf in video store
By announcer, as Sean Penn walked to stage.
mention by roger while he is in the plane awaiting take off
mentioned by Holt
Subject of a $1,000 clue in the category "Oscars Since 2000"
Listed as a movie adapted from a Dennis Lehane novel
Mentioned by David before he chooses Gran Torino as one of his top three international movies as another movie directed by Clint Eastwood.
Dave is watching Vampires (1998) on the TV in the middle of the night.
Some clips from this movie are shown during an interview with Tim Robbins.
footage courtesy of: Scenes from "Mystic River" courtesy of Warner Bros. Pictures
a clip is shown in a montage of Kevin Bacon films
Billy Crystal is wearing a tattoo of an Oscar on his back as he stares out the window; Crystal points at Sean Penn like Kevin Bacon at the parade scene in the end of the film