Spencer Tracy's eleven-minute closing speech was filmed in one take using multiple cameras shooting simultaneously.
Maximilian Schell's Oscar for Best Actor makes him the lowest-billed lead category winner in history. He is billed fifth, after Spencer Tracy, Burt Lancaster, Richard Widmark, and Marlene Dietrich.
Many of the actors involved in the film did so for a fraction of their usual salaries because they felt the subject matter was so important.
Watching Maximilian Schell shoot a scene one day, Spencer Tracy said to Richard Widmark, "We've got to watch out for that young man. He's very good. He's going to walk away with the Oscar for this picture." This is exactly what happened. In another version of this story, Tracy went up to Widmark and said, "Dick, we're in trouble."
Marlon Brando wanted to play the role of Hans Rolfe, the German lawyer who defends the German judges. Brando actually approached director Stanley Kramer about it. Although Kramer and screenwriter Abby Mann were very intrigued with the idea of having an actor of Brando's star power in the role, both were so impressed with Maximilian Schell's portrayal of the same part in the original television broadcast Judgment at Nuremberg (1959) that they had decided to stick with the relatively unknown Schell, who later won the Oscar for Best Actor for that role.