Jeremy Renner fractured his right elbow and left wrist while filming a stunt for the movie. As a result, some scenes required him to wear green casts that would be edited out later.
The film was based on the true events of the lives of former high school classmates (Bill Akers, Patrick Schultheis, Sean Raftis and Mike Konesky). As teenagers during the 1980s, they would entertain themselves by playing the schoolyard game during breaks at Gonzaga Preparatory School in Spokane, Washington.
In contrast to the movie, in the real game of tag there are 10 friends participating, the game is played each February, and they don't tag each other at work. However, the tag at a father's funeral did happen, and in both the game has been an unconventional way of maintaining friendships.
Brian Dennehy has an uncredited role in the movie as Chilli's father. One of the "Tag Brothers" that the movie is based on is also named Brian Dennehy.
The booby traps and sound effects used for the chase sequence in the woods are direct callbacks to Predator (1987).