Jonathan Lipnicki showed up on the set one day telling everyone that "the human head weighs eight pounds". Writer, producer, and director Cameron Crowe liked it so much he wrote it into the script.
Renée Zellweger admitted that the day she was cast in this movie, it had been so long since she had worked that when she went to an ATM, she did not have enough of a balance to make a withdrawal.
The scene in which Jerry Maguire (Tom Cruise) and Ray Boyd (Jonathan Lipnicki) are talking in the living room for the first time, was completely ad-libbed. Cameron Crowe wanted to create a genuine "feel" between the two and did so by not having written dialogue for that particular scene.
Renée Zellweger auditioned three times with Tom Cruise and later received a personal call from Cameron Crowe while she was attending the Sundance Film Festival. Crowe thanked her for her time, and she thanked him for being considered, and just as the call was about to end, Crowe asked, "Well, do you want the job?"
Two lines from this movie, "Show me the money" and "You had me at hello", are in the AFI's Top 100 movie quotes (at numbers twenty-five and fifty-two, respectively).
Jerry Cantrell: Guitarist/vocalist of Alice in Chains is the Copymat worker at the FedEx store commending Jerry for putting his balls out there.