The script was inspired by Edward Albee's The Zoo Story.
Alien in the Park was written to be a pilot for a series called Park Avenue Stories. The Queen who appears at the end was also the host for the show.
The pickle that Joe eats on screen was from the film's sponsor, Bubbies. Emilio Palame would often spit out the pickle between takes because he didn't care for the taste.
Due to minimal setups required for the shoot, principle photography was completed within one 12-hour day.