When the Bernie Sanders-aligned Our Revolution endorsed Tom Steyer in the unwieldy California governor’s race, the irony of a progressive group founded on an anti-billionaire ethos backing a multibillionaire wasn’t lost on its leader.

“If you had asked me a year ago, ‘Oh, are you going to endorse a billionaire for anything? I think that would have been highly unlikely,” Joseph Geevarghese, Our Revolution’s executive director, said in an interview.

But Geevarghese said he’d been impressed with Steyer’s policy platform and engagement with liberal groups in the state.

“The most energizing and ideologically aligned candidate just happens to be a billionaire,” he said.

The unexpected alliance between progressives and Steyer — a hedge fund founder who’s faced criticism for past investments in controversial spaces like private prisons — has helped vault him into the top tier of a California governor’s race that lacks a clear favorite one month out from the all-party primary.

Despite initial skepticism from liberal groups and politicians in the biggest Democratic state in the country, Steyer managed to stay in the conversation with his consistent push for progressive priorities, like single-payer health care, taxing the profits of oil companies and a billionaire tax that is likely to appear on the ballot this fall.

Former Rep. Eric Swalwell’s exit from the crowded race last month and the struggles of other progressive candidates — including former Rep. Katie Porter, who’s backed by Sen. Elizabeth Warren — to gain traction helped further clear a lane for Steyer as he pumped more than $120 million of his own money into his campaign.

Irene Kao, the executive director of the progressive group Courage California, said their endorsement of Steyer in April “came as a surprise to us.” “But a lot of our work has to do with holding corporations and the wealthy accountable — so in some ways, we feel like it is a good thing that voters and people are approaching Tom Steyer in this race with that sort of skepticism and holding him to account, trying to get him to respond to his past investments and to talk about his story and development since then,” Kao said.

“But again,” she added, “it is really important for people to be really wary about the wealthy, how they generated their wealth and what they do with it.”

Steyer has noted that his hedge fund sold its holdings in the private prison space and that he exited the fund itself in 2012. He has apologized for the investment too, calling it a “mistake” and has run ads responding to the criticism.

Democratic state Rep. Alex Lee, the chair of the California Legislative Progressive Caucus, was one of the first state lawmakers to endorse Steyer in February. But even he recalled feeling “skeptical” about Steyer when he heard that he was running.

“I’m very sympathetic to voters who are skeptical of voting for a billionaire,” he said.

But as the field became clearer in recent months, Lee felt like Steyer had firmly taken over the progressive lane among Democrats in the race.

“Frankly, look at the other options,” Lee said.

Progressive support for Steyer didn’t come out of nowhere. Following his career at Farallon Capital, Steyer emerged as an outspoken climate advocate and founded NextGen America, a progressive PAC working on climate, health care and reproductive rights. His unsuccessful 2020 presidential run focused heavily on climate issues.

Steyer launched his gubernatorial campaign in November, and even before his latest endorsements, he’d already secured the backing of the state’s largest nursing union.

Still, even after deploying his massive war chest and picking up a stream of progressive endorsements, Steyer remains lumped together with a handful of other candidates in the polls in the race to succeed Gov. Gavin Newsom. Candidates from all parties will appear on the same June 2 primary ballot, with the top two vote-getters advancing to the November general election.

Democrats have been desperate to unite behind one candidate to avoid a dreaded outcome of two Republicans emerging, but have struggled to do so. Ballots go out in the mail for early voting this weekend.

At the outset of the race, many Democrats assumed that the progressive lane was Porter’s to lose. A former student of Warren’s, Porter rose to prominence as a member of Congress for her sharp questioning of Trump administration officials during his first term and for her use of whiteboards to help unwind how big pharmaceutical companies hiked drug prices and to uncoil bank fraud scandals.

But her gubernatorial campaign got off to a rocky start after videos showing her yelling at a staffer and engaging in a tense interview with a local TV reporter both made waves nationally. (Porter apologized after each clip surfaced last year).

Progressive groups and lawmakers acknowledged that those videos contributed to their decisions to endorse Steyer.

“Some of that came up,” Geevarghese said. Kao said the videos “certainly were part of the equation.”

But California progressives also said they had questions about Porter’s consistency when it came to certain policies, and they ultimately felt that Steyer had simply advocated for their priorities more forcefully and more frequently.

Lee, who had endorsed Porter during her unsuccessful 2024 Senate run, said he chose Steyer this time around because he is “running a progressive policy-first campaign and that is what a lot of people wanted to see — and I just think people didn’t feel that or see that her in her gubernatorial run.”

Nonetheless, Porter has been endorsed by a number of prominent progressive elected officials, including Warren — who appeared in a campaign ad for her released Friday — Rep. Robert Garcia, D-Calif., and the group End Citizens United. A tracking poll released April 20 by the California Democratic Party found that Porter was still earning the most support among self-identified progressive voters.

“Steyer made his billions off of investments in Big Oil, Wall Street, and private prisons — the very industries that Katie’s spent her entire career holding accountable. Katie has consistently fought for disenfranchised Californians, while Steyer’s fought only for himself,” Porter campaign spokesperson Peter Opitz said in a statement.

Meanwhile, progressives interviewed by NBC News also offered criticism of former Health and Human Services Secretary Xavier Becerra, who’s seen his standing in the polls rise following Swalwell’s exit.

“I get very bristled by the fact that people are trying to pretend that he’s something he’s not. He has never on the campaign trail even claimed to be progressive,” Lee said.

Lee and others have criticized Becerra in particular for his role in handling the migrant crisis when he was in the Biden administration; for refusing to release certain police records related to officers who used deadly force when he was California’s attorney general; and for taking campaign contributions from Chevron.

A Becerra campaign spokesperson didn’t respond to questions from NBC News.

Recent polls show the gubernatorial field remains jumbled. A CBS News/YouGov survey released this week showed that 15% of registered voters backed Steyer. Becerra was at 13%, Porter was at 9% and no other Democrat had above 4%.

The poll also found that the two prominent Republicans in the race — former Fox News host Steve Hilton and Riverside County Sheriff Chad Bianco — were still in the top tier. Hilton, who is endorsed by President Donald Trump, led all candidates, with 16%, while Bianco got 10%. All of these top-polling candidates fell within the survey’s margin of error.

A debate Tuesday night at Pomona College featured frequent sparring between Becerra and Hilton, as both candidates attempted to appear as their party’s frontrunners. They’ll all meet again for two debates on Tuesday and Wednesday.

As for Steyer, he repeatedly referred to himself during his closing statement as a “change agent” and made the case for why progressives should rally around him.

“We’re going to have to take on the corporate special interests that are driving up your costs and profiting off you,” Steyer said. “I am the person who is willing to do that. I am the change agent.”

“The people who support me are progressive — progressives, environmentalists and unions, including teachers and nurses,” he added. “If you want change, there’s only one person on this stage they’re scared of.”