During an interview Christopher Walken said he portrayed his somewhat "friendly" demeanor as Sgt. Toomey due to meeting an on set military consultant who was a "very tough Drill Sgt." But at the same time he also described him as a "very nice, soft-spoken man", whom everyone feared, but he didn't have to sound or look fearful. In meeting this man, he decided to incorporate both types of people in his character, which was almost a 180 degree difference from the stage play character Sgt. Toomey.
Matthew Broderick, Matt Mulhern, and Penelope Ann Miller all reprized their Broadway roles in the film.
According to Corey Parker (who played Epstein), "the scariest experience during the shoot" was when Christopher Walken was "plastered" during the filming of "the scene where Walken is supposed to be drunk and is carrying a pistol." His "lines were gone," so a script supervisor had to feed him individual lines.
Broderick had just completed this film when on a driving vacation in Northern Ireland with then girlfriend Jennifer Grey, they were involved in a head-on collision in which a mother and daughter in the other car died.
The movie differs from the play in significant ways. In the play, the climactic confrontation is between Sergeant Toomey and Arnold Epstein, not Eugene Jerome. Also, the play is set in 1943, not the movie's 1945. The final train ride is towards an Atlantic seaport for deployment overseas. According to Corey Parker (who played Epstein), the movie originally also was supposed to end that way, but the voiceover was later changed.