In the 1960s, screenwriter Larry Cohen pitched Alfred Hitchcock the idea of a real-time film confined entirely to a phone booth, but they could never devise a plot that justified why the action had to stay in one location.

Cohen only found the missing piece of the puzzle in the late 1990s, decades after Hitchcock's death, when he conceived of a sniper forcing the protagonist to remain in the booth, which finally allowed him to write the script.

The script attracted several A-list actors including Tom Cruise, Will Smith, Mel Gibson, Robin Williams, Anthony Hopkins, and Nicolas Cage, while directors considered included Mel Gibson, Steven Spielberg, the Hughes brothers, and Michael Bay.

Michael Bay was dropped from consideration as director after his first question about the script was reportedly, "OK, how do we get this thing out of the damn telephone booth?"

Jim Carrey was originally cast as Stu Shepard and was even fitted for his suit before dropping out due to cold feet shortly before shooting began.

Ron Eldard originally played The Caller and filmed all his scenes delivering lines from a window across from the phone booth, but he was recast with Kiefer Sutherland after Cohen felt his voice lacked the necessary mesmerizing tone; Sutherland then re-recorded all of The Caller's dialogue for the final film.

Colin Farrell used a fake Bronx-style American accent for the role, while his Australian co-star Radha Mitchell also adopted a fake American accent to play his wife.

Principal photography took only ten days, plus two additional days for establishing shots, pickups, and re-shoots, aided by using "French hours" that eliminated the typical lunch break in favor of food being available throughout the shooting day.

Although set in New York City, the film was actually shot in downtown Los Angeles in November 2000, at the corner of West 5th Street and Frank Court, a fact given away by passing LACMTA buses and a black gate visible in the background.

Because the film was shot in chronological order, costume designer Daniel Orlandi could let Colin Farrell's Dolce & Gabbana suit sustain progressive damage without slowing production, since backup copies of the suit didn't arrive from the fashion house until the last day of shooting.

The film is structured to unfold in real time, so its runtime matches the actual duration of the story's events, and like the TV series 24 (which also starred Kiefer Sutherland), it makes use of split-screen techniques.

The film's original November 2002 theatrical release was postponed by 20th Century Fox to April 2003 because the real-life Beltway sniper attacks occurred in the Washington, D.C. area that October.