After discovering that the character "Officer Obie" was modeled after him, actual Stockbridge (Massachusetts) Sheriff William Obanhein demanded that he play the role himself. His reason: "If anyone is going to make a fool out of me, it might as well be me!"
Although many people regarded Arlo Guthrie's recording of "The Alice's Restaurant Massacree" to be fiction, Arthur Penn, who owns a home in Stockbridge where the story takes place, realized it was for the most part based on events that had actually taken place. Therefore, what appears to be a continuity problem is in fact a correct representation of the facts. The movie portrays the actual photos used as evidence at the trial. The real life "blind judge" in Guthrie's song, "Judge James Hannon", also plays himself (James Hannon) in the film.
Tina Chen, who played Arlo Guthrie's on-screen girlfriend, wore an authentic Chinese dress that had belonged to her grandmother. When they wrapped up the shoot, the film crew put the dress in storage. She never got it back.
The real Alice Brock and Ray Brock appear as extras in the film. In the scene where "Ray" is putting up insulation, she is wearing a brown turtleneck and has her hair in a ponytail. In the Thanksgiving scene she wears a bright pink satin blouse. In the party scene she's wearing a Western-style dress.