David Duke did not discover that Ron Stallworth was a black man until 2006, when a Miami Herald reporter contacted him for his side of the story.

The film featured the late musician Prince singing "Mary, Don't You Weep" over the end credits. This was a previously unreleased live rehearsal recording.

The real David Duke called Ron Stallworth to express his concern over his "baffoonish, cartoonish idiot" portrayal in the film. Duke also said he respected director Spike Lee. After seeing the film, he was not pleased that the film did not follow the events of the book.

Director Spike Lee and his writers moved the story back seven years from when it actually took place in 1979 to 1972. This allowed the film to reference both the then trendy blaxploitation movies and the re-election campaign, supposedly supported by the Klan, of President Richard Nixon.

Contrary to popular belief, the real 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, but they never answered.

This was the first Spike Lee film since Oldboy (2013) to be shot on film. Although the past three or four films of his were all digital, Lee expressed his passion for shooting on celluloid film.

During an interview with Dave Karger at the 2018 Cannes Film Festival, Topher Grace said that once he got the role and during the filming, he was not allowed to tell anyone that he was playing David Duke.

At a post-film cast Q&A on August 11, 2018, actor John David Washington revealed that right before his character's post-KKK gun shooting scene was filmed, director Spike Lee told him that the metal targets depicting black men running were not props and that they were purchased on the Internet. Washington said filming that scene with that knowledge affected his performance.

John David Washington is the son of Denzel Washington, who appeared in four films directed by Spike Lee.

Coincidentally, John David Washington made his film debut as a six-year-old Harlem classroom student in Spike Lee's Malcolm X (1992), which featured his father, Denzel Washington, and his grandmother, Lennis Washington.

Director Spike Lee received a six-minute standing ovation at the Cannes Film Festival after the premier of the film.

The real Ron Stallworth had originally wanted Denzel Washington play him, but was ecstatic to find out his younger son got the role.

Mr. Turrentine (Isiah Whitlock Jr) says his trademark "Sheeeeeee-it" spoken by his character Clay Davis from The Wire (2002).

Both director Spike Lee and star John David Washington are graduates of the Historically Black College/University (HBCU) Morehouse College in Atlanta, Georgia. (Frequent Spike Lee collaborator Sam Jackson is also a graduate).

Robert John Burke co-starred with John David Washington's father, Denzel Washington, in Safe House (2012).

On May 19, 2018, Spike Lee won the Grand Prix at the Cannes Film Festival; May 19 was Malcolm X's birthday. Lee directed Denzel Washington (John David Washington's father) in Malcolm X (1992).