Lael Brainard missed her chance to become the second-ever woman to lead the Fed — but insiders say she’s now poised to become a powerful, left-leaning force shaping US fiscal policy.

The 59-year-old, Harvard-trained economist — who progressive lawmakers including Sen. Elizabeth Warren had favored to succeed Jerome Powell to lead the central bank — was instead nominated to become vice chair of the Fed.

While the No. 2 spot lacks the pivotal power of the chairman’s role, insiders say Brainard nevertheless is now a prime candidate to succeed Powell when his second term ends — or possibly succeed Janet Yellen as Treasury Secretary, experts said.

“This absolutely positions her as Fed Chair or Treasury Secretary,” said Ian Katz of Capital Alpha Partners.

Since 2018, Brainard has dissented 20 times in votes to loosen restrictions on Wall Street. In 2016, Brainard — two years into her stint as a Fed governor — gave $2,700 to Hillary Clinton’s presidential campaign.

“She’s a partisan,” one person with knowledge of Brainard’s approach told The Post. “But no one is a dictator at The Fed — she’ll need buy in from the board of governors.”

Likewise, Republicans expect Brainard to tone down the rhetoric against the fossil fuel industry during confirmation hearings. In brief remarks at the White House on Monday, she said, “I’m committed to putting working Americans at the center of my work at the Federal Reserve.”

“I don’t think Lael can single-handedly make The Fed more activist on climate issues but she will be out there talking about it more than another person in that position would be,” Katz told The Post. “She has the seniority and influence and self-confidence to make the job what she wants.”