In an interview, Juliana Donald (Jenny) recalled how filming of the jogging scene in the park was temporarily delayed by a camera problem. In wide eyed amazement, a little boy passing by approached and started talking to Kermit the Frog, oblivious to Jim Henson operating him. Despite the surrounding commotion of technicians trying to fix the camera issue, Jim started interacting with the boy. Moments later, Jim found himself doing an impromptu performance with Kermit for an entire group of children who had gathered around to watch. Juliana said, "It was so memorable to me because time just stopped. It was a wonderfully magical moment where you experience someone's true joy with their work."
Rizzo the Rat appeared throughout the final season of The Muppet Show (1976) and along with Scooter as the Happiness Hotel bellhops in The Great Muppet Caper (1981), but this is his first major role with The Muppets and his first appearance with his more "wiseguy" personality.
The soundtrack to this movie is the only theatrical Muppet movie soundtrack to have never been available on CD. However, three songs from the film ("Together Again," "I'm Gonna Always Love You," and "He'll Make Me Happy") were released on The Muppets music collection "Music, Mayhem and More!".
The scene of Miss Piggy singing "Saying Goodbye" with Kermit was filmed at the Lackawanna Rail Terminal in Hoboken, New Jersey. The train Piggy is on is an electric train designed and built by Thomas A. Edison.
The scene where Kermit the Frog graduates from college was filmed at Vassar College in New York. Director Frank Oz wanted it shot in front of the most academic looking building on the campus: the dining hall.
As with The Muppet Movie (1979), this can be read as an allegory of Jim Henson's career. Like his creator, Kermit gains local popularity performing during his college years, decides to try his luck in New York, struggles, takes an unlikely detour into the world of advertising, then gets his big break.
Speaking on the film's MPAA rating, Jim Henson said, "There have been only four G movies this year. Isn't that amazing? I would never do a Muppet movie that wasn't a G. It's said that the G rating has a stigma. Kids don't want to see kiddie movies anymore."
When one of the rats is mixing batter by using an eggbeater as an exercise bike, the effects crew mixed several chemicals together to resemble batter. They somehow created a corrosive substance that was eating right through the mixing bowls and they feared was toxic. Finally a female crewmember made some actual pancake batter, which they used for the final scene.
The teaser trailer for the film was composed entirely of footage created independently of the film. A breathless announcer describes the excitement and spectacle of Broadway, and the many hopefuls who come to New York seeking stardom. Kermit and Miss Piggy only appear briefly at the end of the trailer.
Jim Henson initially planned to film the project in late spring 1983. Having directed The Great Muppet Caper (1981) and The Dark Crystal (1982) back-to-back, Henson decided to serve as the producer along with David Lazer. Upon selecting Frank Oz to handle directorial duties, Henson stated, "I was looking at the year ahead and I thought my life was very busy and I thought maybe it was a time to have Frank directing one of these."
The first draft titled The Muppets: The Legend Continues, written by Muppet Caper scribes Jay Tarses and Tom Patchett, was dismissed by Frank Oz for being "way too over jokey". After being given Jim Henson's encouragement to tinker with the script, Oz revised the screenplay in an effort to develop the "oomph of the characters and their relationships"
When one of the rats is greasing the grill by skating on it with pats of butter on his feet, the effects crew tried several ways to get the proper sizzling effect. In the end, actual butter on a hot surface worked just fine.
The film's title references the 1925 song "Manhattan," by Lorenz Hart and Richard Rodgers, with its lyric "I'll take Manhattan, the Bronx, and Staten Island too." The Muppets popularized the phrase "Take Manhattan" as a title, which other films and TV series have used since.
Gregory Hines: Lends Miss Piggy his roller skates so that she may chase down the purse-snatcher. Also participates in Kermit the Frog and Miss Piggy's reunion/confrontation immediately after the chase.
Both the storybook and comic book adaptations of the film include scenes that were presumably filmed but deleted. Both versions include a sequence where Rizzo and Gonzo attempt to cure Kermit's amnesia, a scene where Gonzo tells Kermit the Frog that the wedding minister is a real one, and an allusion to Beauregard taking The Electric Mayhem to New York. The storybook also has a scene of Dr. Bunsen Honeydew performing a bizarre experiment on Animal.