Barely a month ago, a veritable who’s who of Hollywood A-listers turned out for President Joe Biden. The event, organized by former DreamWorks Animation Chief Executive Jeffrey Katzenberg, drew George Clooney, Barbra Streisand and Julia Roberts.

Jimmy Kimmel moderated an interview with Biden and former President Barack Obama at the gathering in downtown Los Angeles’ Peacock Theater. Sheryl Lee Ralph sang and Jack Black entertained the star-studded crowd wearing a pair of American flag overalls.

The evening raised more than $30 million, the largest one-night campaign haul in Democratic history.

But behind the fawning praise and laughs, cracks began to appear in the public façade.

Some of the most powerful members of Hollywood, who had steadfastly supported the president, harbored some serious reservations about the 81-year-old’s mental acuity.

At times during the event, Biden’s answers meandered and Obama occasionally jumped in to redirect the conversation.

Then came Biden’s disastrous debate performance. And those very same industry stalwarts who had just feted Biden began saying he should not seek reelection.

“Lost” co-creator Damon Lindelof, who attended the fundraiser, was one of the first to publicly call for Biden to step aside. “Biden has to go & the Dems need to wake up,” he wrote in a column for Deadline, adding that donors should withhold checks until he did so. Within days others followed suit. Netflix co-founder and major Democratic donor Reed Hastings also called on Biden to end his reelection bid.

The most damaging blow came a week later, when Clooney wrote a blistering Op-Ed for the New York Times, saying, “The Joe Biden I was with three weeks ago at the fundraiser was not the Joe ‘big F-ing deal’ Biden of 2010. He wasn’t even the Joe Biden of 2020. He was the same man we all witnessed at the debate.”

Clooney’s public excoriation proved to be a tipping point, creating a public relations disaster for the Biden campaign, said a confidant close to a senior Democratic leader who was not authorized to speak publicly. Soon others — including actor-filmmaker Rob Reiner — began airing similar sentiments, contributing to the pressure that culminated in the incumbent president’s extraordinary decision to drop out as the Democratic nominee.

The remarkable turn of events underlined the outsize role that Hollywood — long known as the “ATM of the Democratic Party” — plays in political campaigns and the money that fuels them.

“In the world of politics, money is what drives these things, and the fact that many in Hollywood closed up their checkbooks had a very big impact,” said Steve Caplan, adjunct instructor of public relations and advertising at the USC Annenberg School for Communication and Journalism.

Now, entertainment heavyweights are putting their money behind Vice President Kamala Harris’ White House campaign. Hastings contributed $7 million to a super PAC supporting Harris, the largest donation that he has made to a single candidate, said a person close to the Netflix co-founder who was not authorized to comment. The Information first reported the donation.

“We are all in for Kamala and have been since the moment she announced,” said Andy Spahn, a Los Angeles political consultant to media moguls such as Katzenberg and Steven Spielberg. “Tremendous excitement and energy here around Kamala’s candidacy. We are all in.”

Unease over Biden’s gaffes

For months, Biden’s gaffes and stumbles became hard to ignore. He fell walking up the stairs to Air Force One; he mixed up Syria and Libya at a news conference and called Kamala Harris “Vice President Trump.”

While allies and critics alike began commenting, the campaign dismissed their concerns as isolated incidents; Biden described his debate performance as a “bad night.”

As momentum for Biden sputtered and his failings became more publicly evident, some supporters vented their frustration toward Katzenberg, one of the campaign’s co-chairs, who assured them Biden was on his game, even calling his age his “superpower.”

Katzenberg took to making comparisons to Harrison Ford starring in a new Indiana Jones movie at 80 and Mick Jagger performing on tour with the Rolling Stones, also while turning 80, the Wall Street Journal first reported.

Katzenberg declined to comment.

But Biden’s lackluster approval ratings and an unmistakable enthusiasm gap continued apace, particularly among celebrities, who were not jumping on to endorse the campaign.

Even before the debate, it was difficult to get industry players to publicly back Biden, according to someone who works closely with celebrity surrogates and was not authorized to speak publicly.

“There was a general lack of enthusiasm. Some wanted to bury their heads in the sand, and there was a legitimate group of people who felt that there was a value misalignment with what was happening in the Middle East and a larger group that did not see the benefit in speaking out,” said this individual. “It was extremely difficult, even with stalwarts.”

While Clooney and others had taken public stands, this person said there were a number of private conversations going on between about 40 prominent artists and the campaign’s leadership.

John Legend, the Grammy-winning singer, shared the concerns about Biden’s viability in an interview.

“There would be a lot of challenges to overcome if we stayed with Biden and to defeat Trump with him as our nominee,” Legend told The Times. “For months the American people were telling us that they didn’t like either choice.”

Within days of each other, Disney heir Abigail Disney and billionaire media mogul Barry Diller said they were halting any further financial support to the Biden campaign.

Speaking at the Aspen Ideas Festival, Endeavor chief Ari Emanuel took Biden’s advisers to task for their lack of candor about his health and criticized the president for backtracking on his pledge to pass the baton after one term.

“I had a father who died at 92, but at 81 I took away his car, and it was a very simple test for me,” said Emanuel, whose brother Rahm Emanuel served as Obama’s White House chief of staff. “If you were driving from downtown Beverly Hills to Malibu, would you want Biden to do it at night?”

A dramatic shift toward Harris

On Sunday, Biden announced he would not carry on as the Democratic nominee and endorsed Harris.

It was as if the tide turned — at least in Hollywood.

“Oh God. People, and I mean this sincerely, people are giddy. They are not just happy, they are giddy,” said Donna Bojarsky, a longtime Democratic political consultant and co-founder of a nonprofit dedicated to building civic engagement in L.A. “I haven’t seen this much excitement since Barack Obama or Joe Biden’s [2020] election. … And only now are we realizing how incredibly difficult and depressing this previous situation was. Now, it’s as if an anvil has been lifted off.”

Within 24 hours, a growing list of marquee names from movies, TV, fashion, music and media including Jamie Lee Curtis, Spike Lee, Questlove and Ariana Grande signaled their support for Harris, who is widely expected to take over as her party’s presidential nominee. Beyoncé gave Harris permission to use her song “Freedom” for her presidential campaign.

“There is an increased excitement — the feeing is palpable,” said Legend. “There is an optimism that people are feeling now that they were not feeling before that we can ride this moment to victory.”

Many of those who had blasted Biden and his advisors are now galvanized around Harris, whose husband, Doug Emhoff, is a prominent Los Angeles entertainment attorney.

At the top of the list was Clooney, who in a statement to CNN praised Biden for exhibiting “true leadership,” adding, “We’re all so excited to do whatever we can to support Vice President Harris in her historic quest.”

“An election that was previously characterized by dread and grim resignation is now characterized by the excitement of possibility,” Lindelof wrote in an email to The Times, adding that he has been a “huge fan” of Harris since she first ran for California attorney general in 2010. “I have yet to speak to a single person who hasn’t been deeply impressed by everything she has said … during this emotionally intense and complicated time. We’re wildly inspired by this potential ticket and we’ll give accordingly.’

As the praise and endorsements rolled in, so has the money.

Spahn, the political consultant, noted that Harris raised $81 million in the first 24 hours after Biden announced he would not seek reelection, a record-breaking haul. “More to come,” Spahn said.

Diller told The Times that he and his wife, fashion designer Diane von Furstenberg, plan to give “the maximum” allowed under federal law to the new Democratic presidential nominee.

“I think it was inevitable,” he said of Biden stepping down, noting that his preferred Democratic candidate is Harris, calling her “qualified and competent.”

And Hollywood is gearing up for another glitzy star-studded fundraiser, likely to happen before the Democratic National Convention next month in Chicago, according to two individuals with knowledge of the event.

“The last 24 hours have been a lot of excitement — sign me up, where can I contribute, how do I get involved?” said Wendy Greuel, a former Los Angeles city controller who worked in President Bill Clinton’s administration and for the entertainment firm of DreamWorks SKG. “Whether it’s the entertainment industry, whether it’s activists, it has been a shot in the arm for people to engage or reengage.”

She added that Democrats were boosted by the fact a decision had been made and there is a goal to pursue.

“The sense of limbo was challenging,” Greuel said. “The excitement is we have a plan. We have a mission to defeat Donald Trump and we’re behind Vice President Kamala Harris for president of the United States. It’s a shot in the arm. People appreciate this is the pathway to have a Democratic nominee and everyone is rowing in the same direction.”

Times Staff writer Wendy Lee contributed to this report.