“This is made of success — not everyone can have it,” the actress and comedian Tiffany Haddish said Sunday night, as she held the train on her dress and danced her way through the crowd inside the Wallis Annenberg Center for the Performing Arts in Beverly Hills.

At around 11 p.m., hundreds of people were smiling and nodding and bobbing and weaving their way across a red carpet that snaked its way from Santa Monica Boulevard through the main room of a customized event space where Vanity Fair’s annual post-Oscars party was taking place.

Barry Keoghan, the star of “Saltburn,” stood near the center bar. Lauren Sanchez, the fiancée of the Amazon founder Jeff Bezos, was in front of him, shimmying away to Chic’s “I Want Your Love,” in her reddish, partially see-through chiffon dress.

Never mind that people had been tripping on her train all evening long.

“I don’t mind,” she said. “It just bounces right back up.”

The Vanity Fair party started in 1994 at Morton’s, a celebrity hangout on the corner of Robertson and Melrose. The first few years, only the most famous and connected people in Hollywood were invited.

But the party and the magazine grew together.

First, the party expanded into the parking lot out back. Later, it moved to the Sunset Tower Hotel.

But neither could contain what became the magazine’s central branding event (and a brief move to a parking garage turned out to be a less-than-stellar choice for a party built for snobs).

Over the years, a host of stars began having their own after parties for Hollywood’s biggest night, among them George Clooney, Jay-Z, Prince and Madonna.

A few figured out the exclusivity part. None achieved the size and scale.

Kris Jenner, in a slinky beaded gown, ambled over to Ms. Sanchez to give her a kiss hello. Kim Kardashian joined them a moment later.

Seated by the window at a hightop table was the filmmaker John Waters, who had been at the party since around 3 p.m., when a small percentage of the event’s regulars are invited to arrive for a dinner that takes place during the broadcast.

Less than 24 hours before, Mr. Waters had been in Ocean City, Md., where he hosted a screening and talk for his 1988 movie, “Hairspray.”

“I went home around midnight, lost an hour because of damn daylight savings, got picked up at 4:30, and went to the Philadelphia airport so I could come to this party,” he said. “How’s that for dedication?”

Mr. Waters said that he had loved “Poor Things,” a kaleidoscopic movie about a Frankenstein-like surgeon who implants the brain of a baby into the body of a recently deceased woman.

“Anytime an insane, sex art movie with a $35 million budget becomes an international box office hit, that’s good for me,” he said.

But that wasn’t the real reason he was here. “The whole point is to prove you’re invited,” he said.

A woman approached to tell him how much she loved his films.

Her name was Cathy Scorsese and she was there with her father, Martin.

Turns out, Dad receives Mr. Waters’s annual Christmas card, which last year was accompanied by a blow up doll of the sender.

“That was great,” said Mr. Scorsese, who was now at her side.

Seconds later, they were all taking pictures together.

Upon completion, Sharon Stone bounded up to Mr. Scorsese and gawkers swarmed, eager to capture the director of “Casino” in a picture with the woman who starred in it.

Naturally, they complied.

A few steps away was the television producer Shonda Rhimes, who had been at the dinner.

“I have to go take my Black excellence photo,” she said, darting toward the front of the room with a group that included the actress Tracee Ellis Ross, the actor Jeffrey Wright, the musician Babyface and the filmmaker Ava DuVernay.

Oscar winners arrived, trophies in hand.

One was the singer Billie Eilish, who along with her brother, Finneas O’Connell, became the youngest two-time winner in Oscars history when she won the award for best original song.

This time, they had won it with the song “What Was I Made For?,” from the movie “Barbie.”

She was cradling it as if it were a baby. Asked where she planned to put it when she got home, she replied, “next to the other one.”

Christopher Nolan, whose film “Oppenheimer” was the evening’s biggest winner, did a tour around the room holding his best director statue in one hand and his best picture Oscar in the other.

Then, he darted toward the exits. Universal Studios was also holding a party for the cast and crew of “Oppenheimer.”

By then, it was after midnight and many were making their post-Vanity Fair plans.

Cynthia Erivo, a previous Oscar winner who served as a presenter this year, was out on the deck barefoot. “I think I’m going to go home and change into something more comfy and go to Jay-Z’s party,” she said.

The writer Jeremy O. Harris was bound for a party hosted by Madonna and her manager Guy Oseary.

Da’Vine Joy Randolph, who won the Oscar for best supporting actress earlier in the evening, had plans to go to both.

Into the room walked Sara Marks, the director of special projects at Vanity Fair, who has overseen the event since its inception.

“I think I’ve done six and a half miles of walking tonight,” she said. “Who’s still here?”