After the filmmakers appealed to the MPAA's appeals board to oppose censoring the film, it became the first U.S. film to show a nude woman from the waist up and be granted a Production Code Seal. It was the first of a series of confrontations between filmmakers and the MPAA in the 1960s, that would lead to the abandonment of the Code within five years, in favor of a ratings system.
In a 1999 interview with Robert Osborne, Rod Steiger said he based the silent scream at the end of the film on the faces in Pablo Picasso's masterpiece "Guernica".
The original brownstone building, which served as the setting for the Nazerman Pawn Shop, located at 1642 Park Avenue in Manhattan, no longer exists. The site is now occupied by a four-unit, four-story brick apartment block, that was built in 2010. That building, and the one next to it, were destroyed in a gas explosion in March 2014 that killed eight people.
The music on the radio, in the scene between Ortiz and his girlfriend, is by composer Quincy Jones' "Soul Bossa Nova," which would later be used in the Austin Powers franchise.
While walking the streets of New York City, Nazerman passes a theater advertising The L-Shaped Room (1962), a film that featured Brock Peters, who plays Rodriguez.
Stanley Kubrick, Karel Reisz and Franco Zeffirelli all turned down the opportunity to direct. Kubrick didn't find it exciting, Zeffirelli was keen to break into movie directing from his stage background but felt that the material was too dark for him, and Reisz found it too close to home, having lost both his parents in the Holocaust.
Rod Steiger was highly aggrieved that he lost the Best Actor Oscar to Lee Marvin in _Cat Ballou_ for what Steiger considered to be a lightweight comedic performance. Still, he only had to wait another two years before he too was the recipient of the Best Actor Academy Award, for his performance in In the Heat of the Night (1967).
Rod Steiger was paid $50,000 for his work on the film. This was significantly lower than his usual fee but he was heavily invested in the material and also wanted to work with Sidney Lumet.
Sidney Lumet had originally ruled out Rod Steiger in the lead role, considering him too intense for the part. He was pleasantly surprised when, in conversation with Steiger, the actor agreed that the role needed to be seriously underplayed.
One of the rules that United Artists, who initially flirted with financing the film, insisted on was that there should be no overt depictions in the film of the Holocaust as it was such a depressing subject. Ted Allan, who was the first hire to write the screenplay, found this a difficult thing to work around.
Richard Sylbert's set was deliberately designed to be a series of cages - wire meshes, bars, locks, alarms, etc - to symbolize that even though Sol was no longer in a concentration camp, he was effectively still imprisoned by his memories.
Thelma Oliver didn't realize until filming began that her nude scene would be shot with a full intent of being seen (nudity was usually done over the shoulder). She was highly upset about this but agreed to bare her breasts, thereby creating cinema history.