Trivia

Leonardo DiCaprio described his character as being in a "constant, 24-hour panic attack."

Vera Farmiga met with a real LAPD psychiatrist to prepare for her role. The psychiatrist read the script, and told Farmiga that Madolyn did pretty much everything wrong.

Martin Scorsese really wanted Al Pacino for the role of Costello, because he had never worked with Pacino before, but he turned it down. Jack Nicholson was Scorsese's second choice. Pacino would later go on to appear in Scorsese's The Irishman (2019).

Mark Wahlberg easily fell back on his native accent. Martin Scorsese joked it was so thick, they'd need subtitles.

Leonardo DiCaprio called his one-on-one scene with Jack Nicholson "one of the most memorable moments of my life."

Thomas B. Duffy: the Governor of Massachusetts, swearing in the new Police Academy graduates.

Graham King: The producer of the film appears in photographs as the deceased Jackie Costigan.