Director Sidney Lumet had the actors all stay in the same room for several hours on end and do their lines over and over without filming them. This was to give them a real taste of what it would be like to be cooped up in a room with the same people.
Because the film failed to make a profit, Henry Fonda never received his deferred salary. Despite this setback, he always regarded this film as one of the three best he ever made. The others being The Grapes of Wrath (1940) and The Ox-Bow Incident (1942).
Because the painstaking rehearsals for the film lasted an exhausting two weeks, filming had to be completed in an unprecedented 21 days.
Henry Fonda disliked watching himself on film, so he did not view the whole film in the screening room. However, before he walked out, he said quietly to director Sidney Lumet, "Sidney, it's magnificent."
This film is commonly used in business schools and workshops to illustrate team dynamics and conflict resolution techniques.