Steve Guttenberg turned down the lead role and gave a firm "no" to any other Police Academy sequels that might turn up (and they did). He turned them all down. Two decades later, he expressed in an interview that he regretted turning down the chance to star in the later sequels, and was among the main people trying to make another Police Academy movie.
When Police Academy 4: Citizens on Patrol (1987) was released, acerbic critic Rex Reed swore, "If they make another Police Academy movie, I'll leave the business." At the time, Paul Maslansky said, "Reed's one of the reasons I'm making Police Academy 5. I expect him to be a man of his word." To Maslansky's disappointment, Reed was not.
Regarding his experience working on this film, Rene Auberjonois (Tony) stated, "Why I choose to do things is a mystery to me sometimes. I've done things that, on the face of it, you think, 'why would anybody do Police Academy 5?' I had to look at the role, and see if there's a reason to do it. I did it because it was an opportunity to play a character that nobody else was ever going to let me play. I had a great time doing it, don't regret it for a moment, and I'd do it again in a minute."
Had Steve Guttenberg agreed to appear in the movie, his character Mahoney was to be promoted to Lieutenant at the end of the film.
(At around one hour and seventeen minutes) The scene on the speedboat where Lieutenant Callahan sings "The Ride of the Valkyries" was not in the script. Director Alan Myerson laughed so hard at Leslie Easterbrook's vocal improvisation between takes, that not only did Leslie and a cameraman have to grab Alan to prevent him from falling off the boat, but Alan also decided to use the opera singing as part of the scene itself.