J.M. Shupp was the fussy manager of the Sedgewick Hotel in 1984, and one of the few people on staff who knew the full history of the disturbances occurring on the twelfth floor of the building. But after some newlyweds complained to him about a foul-smelling ghost in their bathroom, Shupp called the Ghostbusters, pressing that they handle things "quickly and quietly, tonight." Despite Ray Stantz's assurances, the Ghostbusters ended up causing mass destruction throughout the hotel, to the point that when they finally caught the offending spook Shupp initially refused to pay the $5,000 bill. However, he relented after Peter Venkman threatened to "put (the ghost) right back." He was eventually replaced as the Sedgewick's manager by John O'Keefe sometime before 1991.
- In the film credits, he is simply called "Hotel Manager." His name comes from the novelization by Richard Mueller.
- In The Real Ghostbusters, he is named Morris P. Grout, although that may be a different character.