It all began with a dinner dance. Well, a banquet, really.

Long before Swifty Lazar corralled celebrities to join him at Spago or Graydon Carter reigned over Vanity Fair’s soiree, the Academy Awards were a party held on May 16, 1929, in a ballroom at the Hollywood Roosevelt hotel. The ceremony lasted barely 15 minutes. The band played all night. What was revealed then would hold true for generations to come: Oscar parties have always been far more entertaining than the awards show itself.

At the Vanity Fair party in 2001, for example, a tipsy Courtney Love marched over to a group of photographers and shouted an expletive after one of Mr. Carter’s gatekeepers refused to let her manager in. A decade later, Sean Young, who starred in the movie “Blade Runner,” was arrested at the Governors Ball, reportedly after she crashed the party and slapped a guard.

On more than one occasion, the evening has ended in fisticuffs. There was the time Richard Johnson, then a Page Six editor, published an item claiming that celebrities planned to boycott the Oscar party of the agent Ed Limato because of his client Mel Gibson. Mr. Gibson’s project “The Passion of the Christ” had recently been criticized as anti-Semitic. Mr. Limato was so insulted he threw a glass of vodka in the editor’s face at — where else? — another Oscar party.

The gatherings are often extravagant and, on occasion, homey affairs. And they reflect the hosts who throw them. Thirty years ago, Dani Janssen, the wife of the actor David Janssen, presided over her Oscar party like a Midwestern den mother, dishing up plates of chicken and vegetable casserole in her Century City penthouse. In the late 1990s, Harvey Weinstein, a founder of Miramax, packed his Oscar parties with ingénues and A-listers to promote his movies. Mr. Weinstein, who is currently on trial for the sexual assault of two women, has been the subject of more than 90 sexual misconduct allegations.

Now it seems almost every celebrity with sway has a fete: Beyoncé and Jay-Z took over the parking garage at the Chateau Marmont in 2018. Madonna and the entertainment mogul Guy Oseary host a party, too. “There is always a vacuum between generations,” Bronwyn Cosgrave, the author of “Made for Each Other: Fashion and the Academy Awards,” said in a recent interview. “But someone always steps in to fill the void.”

In 1929, an orchestra played big-band music in the Blossom Ballroom at the first Academy Awards. Studio bosses had created the Academy of Motion Picture Arts and Sciences in 1927 to promote Hollywood movies. The room was festooned with flowering cherry trees and Japanese lanterns, according to “Made for Each Other.”

There, MGM starlets like Joan Crawford and Marion Davies mingled with studio executives, including Louis B. Mayer, who presided over the affair. Mr. Mayer, a fine dancer, waltzed across the dance floor. Women wore department store dresses or frocks created by costume designers. Only 270 people were there; actors were required to attend. “There was no paparazzi,” Ms. Cosgrave said. “No corporate sponsors. Just power and glamour.”

But some actors, particularly female stars under contract, refused to go in later years, mostly because they resented that their bosses demanded it. There was no need to campaign for an Oscar then; winners were told ahead of the ceremony. Still, the parties prevailed into the early 1940s, a staple of Hollywood chic echoed in the casual gaiety of today’s Golden Globes.

With World War II came a shift. The ceremonies were moved to auditoriums. Big bands and opulent celebrations were scrapped as the cultural mood darkened. Organizers who planned after parties tightened their belts, in line with Americans rationing sugar, coffee and meat. (Austerity would re-emerge from time to time, most notably in the early 1990s, when Americans were in the thrall of a grueling recession. In 2008, parties were canceled altogether after Hollywood writers walked out in late 2007 and the subprime-mortgage meltdown threatened the global economy.)

Glamour had returned in full force by 1953, when the Oscars were first televised, on NBC. Then, the ceremonies were held simultaneously on both coasts: at the Pantages Theater in Hollywood and at the International Theater in New York. With television, Oscar viewing parties emerged. “It sparked everyone having a party in their living room,” Ms. Cosgrave said.

But it was perilous, too, for stars and their fragile egos. “You didn’t want to be seen losing,” said David Friend, who, along with Mr. Carter, the former Vanity Fair editor, wrote “Oscar Night: 75 Years of Hollywood Parties.” “Everybody was watching.”

One of those was Irving Lazar, known as Swifty, a Brooklyn-born deal maker with a voracious appetite for literary culture who represented writers and Hollywood royalty, including Humphrey Bogart, Truman Capote, Ira Gershwin, Lauren Bacall and Cary Grant. He and his wife, Mary, presided over a celebrity-packed party from the mid-1960s until his death, in 1993.

Theirs was a coveted invitation. The party began at the Bistro Garden restaurant, but by 1985 it had landed at Spago, owned by the celebrity chef Wolfgang Puck. Mr. Lazar told The Los Angeles Times that he picked Spago because it was the “in” place to be.

The party did not disappoint. Andy Warhol documented the festivities with his 35-millimeter camera. Raquel Welch and Walter Cronkite supped on duck, salmon and pizza. Johnny Carson and Barry Diller, the entertainment mogul who throws his own annual Oscar bash, were there, too.

“To secure an invitation was tougher than getting a ticket to the Academy Awards themselves,” Richard Zanuck, an Oscar-winning producer, told Vanity Fair in 1994. As Mr. Friend said in a recent interview, “It was the beginning of velvet-rope culture.”

But while Mr. Lazar’s Oscar party may have been the flashiest affair, it wasn’t the only exclusive one. Mr. Friend said Mick Jagger attended an Oscar viewing party at Studio 54 in New York in 1978. (Warhol got around: He was there, too.) Elaine’s, the now-defunct Upper East Side hangout favored by Woody Allen and Tom Wolfe, also held parties.

Ms. Janssen told The New York Times Magazine in 2005 that Mr. Lazar wanted to merge his Oscar party with hers, but her husband said no. “Everybody can go out any night and eat dinner anywhere they want,” she recalled him telling her. “But they cannot eat your food.” Bruce Springsteen came for the sweet potatoes, Ms. Janssen told the magazine. Music producer Quincy Jones fancied her black-eyed peas. “Everybody is nutty about my ham because it’s so sweet,” she said.

After Mr. Lazar died in 1993, a number of people stepped in to fill the void with grand-scale parties of their own. Elton John founded an Oscar gala and viewing party earlier that year to raise money for people affected by H.I.V. and AIDS. In 1994, Mr. Carter, who had recently been named editor of Vanity Fair, threw his hat in the ring.

In an excerpt from “Oscar Night” published in Vanity Fair in 2006, Mr. Carter said he had two ground rules for the Vanity Fair party. First, there would be no V.I.P. area. Second, he would greet guests at the door when they arrived. “My feeling was that if the host appeared to be enjoying himself, others would, too,” he wrote. In his early years, he hired a dance band from Havana. Arrivals had to be staggered because so many celebrities showed up.

One year, an interloper sneaked into the party and nestled herself between John Cleese and Faye Dunaway. The woman had hidden in a bathroom dressed as a staff member until she switched into an evening gown. Another time Mr. Carter turned away a reality television star. “It’s not just about those you invite; it’s about those you don’t invite,” Mr. Carter wrote in his excerpt.

“There was a sense you were bringing the pages of the magazine alive,” Mr. Friend said.

In 2017, Mr. Carter left Vanity Fair. The party continued under the magazine’s new editor, Radhika Jones. Ms. Cosgrave went last year. At one point while she was dancing, she said she got a tap on the shoulder. Someone asked her to step aside because a celebrity, who had arrived late, wanted the dance floor to herself.

Some things in Hollywood never change.