California political kingmaker Will Brown made a surprise endorsement in the governor’s race — throwing his support behind billionaire Tom Steyer.

Brown, the former mayor of San Francisco, said in a statement that he’s known Steyer “for many years” and praised his ability to lead.

“I’ve seen how how he brings a deep understanding of complex issues, a disciplined approach to learning and decision making, and a clear commitment to leading with principle and purpose to everything he does,” Brown said.

“California needs a governor who is fully informed, independent in thought, and focused on what serves the public best,” he continued, “and I believe Tom Steyer embodies those qualities and offers real benefit to the state’s future.”

Steyer shared a video on X featuring Brown hailing the candidate for his “brain power” and independence.

“I am grateful for Willie Brown’s confidence as we work to move the state forward,” Steyer wrote.

The endorsement may have come as a shock to some political observers, given Brown’s past criticism of progressive policies that have contributed to San Francisco’s decline. In the race, Steyer has framed himself as further to the left than some of his challengers in the Democratic primary, promoting policies such as a tax on billionaires and single-payer health care.

Steyer has also branded himself as an outsider candidate, frequently pointing out the millions spent by utility companies and others opposing his campaign, which hasn’t relied on corporate donations.

Brown is viewed as one of the most established insiders in California politics. He’s friends with former House Speaker Nancy Pelosi and played a critical role in the rise of two Democratic stars: Gov. Gavin Newsom and former Vice President Kamala Harris.

While not as well known as Pelosi, the former mayor still carries weight with his political decision-making. Over the past few weeks, members of the race’s crowded Democratic field were spotted meeting with Brown, likely in the hopes of winning his nod.

Ex-Congresswoman Katie Porter posted an April 27 photo with him, saying she is “grateful for his wisdom, his sharp wit, and a deep dive into the future of our state.” San Jose Mayor Matt Mahan on April 23 bragged about his new “pre-debate ritual: lunch with Willie Brown.”

Mahan and Porter are among the lower polling candidates, hovering around 7-8% in recent polling. Steyer meanwhile is fighting for the frontrunner Democrat position against former Health and Human Services chief Xavier Becerra.