Christina Superstar is a popular drag queen performer in the film's club circuit. For the first party Michael Alig organizes, he contracts Superstar to provide the music. When James St. James arrives, he finds the club nearly empty. Alig shrugs the issue, contesting that "Christina's here." During the confrontation, Superstar laughs as she observes Alig smash an overhead fire sprinkler, flooding the club. She then leaves the stage to dance beneath the rushing water.
As Alig's reputation and promotion skills increase, he begins to throw higher-scale parties. At one of these events, The King and Queen of Downtown, Superstar is named queen, opposite Keoki Franconi, who is named king. After kissing Franconi on the cheek, Alig releases a bucket of slime over Superstar. As the audience laughs at her, Superstar flails about, prompting club security to subdue her. Superstar begrudgingly returns for Alig's Disco Truck Party, where attendees party in the trailer of a cargo truck. Superstar is meant to drive the truck during the party, however St. James finds her drugged in the cab. In spite of this, Superstar still attempts to drive the vehicle, but police arrive and apprehend the partygoers. Superstar is later revealed to have died, although the cause is not made clear.
Marilyn Manson was interviewed on the set of Party Monster, along with several other actors in the film. Clips of Manson speaking about Superstar's costumes, the experience of Macaulay Culkin buying him a pack of cigarettes and his reason for accepting the role of Superstar were included as bonus material for the DVD release of Party Monster. On each topic, Manson had the following responses:
- "I mean some of the outfits are so absurd, you'd think "How would someone come up with these?" But I think someone like Christina would come up with some of these outfits so... I think my favorite one though is the very first scene where you see me and I'm wearing the "leopard-print tube dress," as they call them. It's very beautiful."
- "The key to Christina is she just never really has a lit cigarette 'cause she's just too fucking busy to light a cigarette. It's just part of... It looks nice, it's a Virginia Slims Light. Macaulay Culkin bought me my first pack of cigarettes and they ID'd him. They didn't know who he was."
- "You know, there's a bit of an inside joke with someone like him or someone like me being in the movie because of who we are. But I think that, at least subjectively looking at him and his role, he's really become Michael Alig and I think that's great. You know, I don't look at him and see Macaulay Culkin. Hopefully people won't look at me and see Marilyn Manson, they'll see Christina."
- "I've been approached for years to do films but, always things that were just too predictable, and some people might find this predictable but in a way I thought it was just so offbeat and Christina's not like me getting dressed up in drag. Christina was just a complete bizarre creation of her own and of Michael's so you know, it was something that I had to act. I'm not playing myself so I was always looking for something that is actually a challenge so Christina was something that I really had to get into character for. So that was enjoyable for me."
Manson's portrayal of Superstar is similar to his appearance in the music video for Nine Inch Nails' "Starfuckers, Inc.". The artist provided his own prosthetic breasts, butt and blonde wig for shooting. For his performance as Superstar, Manson sung an electropop song called "The La La Song" during his inaugural scene. This song is available on Party Monster: Original Motion Picture Soundtrack. Apart from babbles and screams, Manson's only true speaking line in the film is "How do you like my UFO?" Christina asks this to James St. James when he discovers her in the Disco Truck cab, as she reveals an LSD tab on her tongue.