Chris Evans did his own car stunts. Before production began, he was trained for five weeks at a Los Angeles stunt school. Most of the stunts are done by the actors themselves.
On the 5 August 2004 edition of The Tonight Show with Jay Leno (1992), Kim Basinger said that when she was talking on a cellular phone while standing outside a movie house bathroom waiting for a friend, she became very annoyed at the small, rude crowd that had gathered around to point and laugh at her. It was only after her friend exited the bathroom and pointed out that Basinger was standing directly in front of poster for "Cellular" that depicted her talking on a cellular phone did she understand why everyone was laughing at her.
Larry Cohen worked on the script while he tried to get his screenplay Phone Game (2002) sold. In a New Yorker article he says he wrote the film with the intention that it would be the direct opposite to Phone Booth (Phone Booth is about a man trapped on a phone in a booth, while this movie is about a man who is still trapped on a phone but can go anywhere). However, his friends told him that he had written the same screenplay twice.
Inspired partly by the LAPD Rampart scandals in 1999.
The owner of the car Ryan steals was originally supposed to be Simon Cowell portraying himself, but he was unable to accept the part. When Rick Hoffman took the role, the character was changed to an irate lawyer.