Jock Mulligan was the Mayor of New York City during 1991; the year in which the events in Ghostbusters: The Video Game took place.
Jock Mulligan was elected Mayor with a pro-Ghostbusters platform.  Some have said the Ghostbusters' endorsement is what got Mulligan elected. It is inferred that he was elected to office following Mayor Lenny's bid for governor in 1990. Since then, he has capitalized on the fame brought to the Big Apple by the Ghostbusters, particularly maximizing the tourism value of the New York City Public Library and the Manhattan Museum of Art as former sites of the Ghostbusters coming to the aid to the city against supernatural threats.
It is later revealed that during the months up to and following his re-election, Mulligan was possessed by the ghost of Ivo Shandor,  which is what led him to start the Gozerian mythology craze at both the library and the Museum of Natural History. Ivo Shandor used Mulligan to follow the old adage of keeping friends close, but keeping enemies closer. Advocating the team and bringing in Walter Peck in order to throw them off his true plans.
At the mausoleum in Central Park Cemetery, the Ghostbusters separate the Mayor and Shandor with steady streams from the Slime Blowers. After the Ghostbusters defeat Shandor and return to the physical plane, Mayor Mulligan regains consciousness while Winston Zeddemore carries him out and he suffers from mild amnesia. The team explains what happened and Mulligan asks if the possession affected his poll numbers. An amused Egon answered by informing him he was re-elected as mayor during the possession.
Mayor Mulligan possesses a friendly but mildly obnoxious demeanor.
Behind the ScenesEdit
Mayor Mulligan is voiced by Brian Doyle-Murray, older brother of Bill Murray, who plays Dr. Peter Venkman. He also played one of the head psychologists at Parkview Psychiatric Hospital in Ghostbusters II, insinuating that the character, (who is only credited as psychologist) had run for and (eventually) succeeded at taking the office of Mayor. It's possible Peter even had a role in motivating him to do so.
- In a script, before the Ghostbusters, Ilyssa Selwyn, and the Mayor flee, he raises a point that Peck shouldn't be left behind. 
- On page 21 of Ghostbusters Issue #1, one of the city officials mentions Jock.
- On page six of Ghostbusters Issue #4, Mulligan is on Walter Peck's speed dial.