Sidney Poitier insisted that the movie be filmed in the North because of an incident in which he and Harry Belafonte were almost killed by Ku Klux Klansmen during a visit to Mississippi. That's why Sparta, IL, was chosen for location filming. Nevertheless, the filmmakers and actors did venture briefly into Tennessee for the outdoor scenes at the cotton plantation, because there was no similar cotton plantation in Illinois that could be used. Poitier slept with a gun under his pillow during production in Tennessee. He did receive threats from local racist thugs, so the shoot was cut short and production returned to Illinois.
This was the first major Hollywood film in color that was lit with proper consideration for an actor with dark skin. Haskell Wexler recognized that standard lighting used in filming produced too much glare on most black actors and others of dark complexion. He toned down the lighting to feature Sidney Poitier with better results.
Rod Steiger was asked by director Norman Jewison to chew gum when playing the part. He resisted at first, but then grew to love the idea, and eventually went through 263 packs of gum during shooting.
The scene that took place at the Police Chief's house featured dialogue that came out of improvisations between Sidney Poitier and Rod Steiger.