J. P. Grosse is the owner of The Muppet Theatre. Although he only made a few appearances on The Muppet Show, his name was often evoked and instilled enough fear in Kermit that he would usually go along with whatever demands were being made in Grosse's name. Most of these "requests" were casually mentioned by Grosse's nephew Scooter, who was nepotistically hired as the show's go-fer in episode 106.
Though he was mentioned often in the show's first season, Grosse did not make his first appearance on The Muppet Show until episode 205. He showed up at The Muppet Theatre again in episode 218, where the homophonic similarities between his name and guest star Jaye P. Morgan's caused much confusion. Although his last appearance on The Muppet Show was in the "Long, Long Ago" medley," the UK Spot in episode 221, he would continue to be mentioned throughout the run of the show. In the Muppets comic strip of September 29, 1981, it was mentioned that his wife owns the newspaper chain.
Grosse has since made appearances in The Muppet Show context in illustrations (The Muppets comic strip, the book Bo Saves the Show, and The Muppet Show Comic Book) and full-bodied form (The Muppet Show on Tour: 2nd Edition).
In Of Muppets and Men, Jim Henson discussed the limitations of the character: "J. P. Grosse was a good concept so long as we didn't see him, but when we introduced him in person, he was just too harsh. You didn't want to have him around."
Grosse also appeared, nameless and often voiceless, in background cameos in the Muppet movies and on Muppets Tonight, uncharacteristically acting in the Muppets' productions without threatening to close them down. On Muppets Tonight, his performers included Kevin Clash, Leslie Carrara-Rudolph, and Allan Trautman.
In a deleted scene from It's a Very Merry Muppet Christmas Movie, Kermit the Frog claims to have inherited the theater from J. P. Grosse, thus implying that he has died. Though the scene was cut, Scooter is later heard telling some chorus girls that his uncle "used to own the theater." However, Jim Lewis, who scripted the project, offered a tongue-in-cheek rebuttal:
- His favorite pet: Muppy, who got his own act in episode 101.
- His favorite act: The Danceros (episode 106) or "Mah Na Mah Na" (The Muppet Show Book).
- His favorite song: "It's Not Where You Start" (episode 115)
- According to Before You Leap, J. P. Grosse was a successful real estate tycoon. (He also owns the J. P. Grosse Collection Agency, according to Episode 218.)
- The Muppet Show
- The Muppet Movie ("The Rainbow Connection" Finale)
- The Muppets Take Manhattan (Wedding Finale)
- The Muppets: A Celebration of 30 Years
- The Muppet Christmas Carol
- Muppet Treasure Island
- Muppets Tonight
Important instances when J.P. Grosse was mentioned but did not appear:
- Episode 101: Juliet Prowse - his pet Muppy wants his own act, his own dressing room...and his own show!
- Episode 104: Ruth Buzzi - he sends a Mechanical Wind-up TV Show Host to replace Kermit.
- Episode 106: Jim Nabors - his nephew Scooter applies for a job as the show's go-fer.
- Episode 202: Zero Mostel - he offers to give Kermit the payroll money if he schedules lady wrestling.
- Episode 214: Elton John - he wants Elton John to perform Bennie and the Jets.
- Episode 410: Kenny Rogers - he sells the mineral rights to the guest star's dressing room to Arabs.
- Episode 415: Anne Murray - he is in the audience and wants to see Scooter do his skateboarding act.
- The Muppet Show Book
- Bo Saves the Show (1982)
- The Muppet Show Comic Book issue #1 - "Kermit's Story"
- Muppet Sherlock Holmes
- The Muppets Character Encyclopedia
- Muppets Meet the Classics: The Phantom of the Opera