Ron Stallworth had originally wanted Denzel Washington to play him, but was ecstatic to find out his son got the role.
According to editor Barry Alexander Brown, there were no deleted scenes for the movie, a rarity in the industry.
Contrary to popular belief, Ron Stallworth never used a "white" voice on the phone. He ironically had to use his real voice or they would have caught him if he slipped out of character. When his white colleagues told him it could not work, he asked what made his voice any different from theirs and they never answered.
Determined to get the role of Felix Kendrickson, Jasper Pääkkönen arrived at his audition in character, speaking in an American accent and refusing to divulge his background until asked directly by Spike Lee. When Pääkkönen revealed he was Finnish, Lee expressed his amazement and told him he had been completely convinced that Pääkkönen was American, and cast him in the role.
John David Washington has said that the toughest time on set was filming the banquet scene. He later called Ron Stallworth to ask how he had contained himself amid such hatred when dealing with the actual KKK.
Spike Lee: ["I got it. I'm gone."] Ron uses the phrase "I got it. I'm gone." This was previously uttered by Mookie in Do the Right Thing (1989), after Da Mayor tells him to "always do the right thing".