Kamala Harris is making history yet again — this time in a manner few could have envisioned.

She already has blazed trails: As San Francisco’s first female district attorney. As California’s first female attorney general. As the second Black woman elected to the U.S. Senate. And, of course, as the country’s first female, first Black and first Asian American vice president.

Now, at a pivotal moment in American history, Harris, a 59-year-old Democrat, is poised to become the Democratic nominee for president, following President Biden’s departure from the race on Sunday.

Kamala Harris greets supporters on election night after winning her U.S. Senate race in 2016.

(Barbara Davidson / Los Angeles Times)

Biden, 81, beset by concerns about his age and electability, dropped out of the race — a decision that Harris called a “selfless and patriotic act” — and endorsed his second-in-command.

If she receives the nomination at the Democratic National Convention in Chicago next month, Harris will become the first woman of color to head a national ticket, and, if she wins, the first female president.

“We have 107 days until Election Day,” Harris said in a statement Sunday. “Together, we will fight. And together, we will win.”

The nonprofit fundraising platform ActBlue said that as of 6 p.m. PDT Sunday, $46.7 million had flowed in from grassroots supporters in the hours since Harris launched her campaign.

Harris — who publicly supported Biden amid calls for him to step down after a disastrous debate performance in June intensified criticism that he was too old and frail to serve four more years — steps into her new role at a time of great turmoil and tension within the Democratic Party.

She undoubtedly will face fierce attacks from Republicans, who have united behind their nominee, Donald Trump, the twice-impeached, criminally convicted former president who narrowly survived an assassination attempt two days before the start of last week’s Republican National Convention.

“I will do everything in my power to unite the Democratic Party — and unite our nation — to defeat Donald Trump and his extreme Project 2025 agenda,” Harris wrote on the social media platform X, referencing the 900-plus-page manifesto written by conservative thought leaders and Trump acolytes.

California Gov. Gavin Newsom — long called a political frenemy of Harris, whose ascent as a Democratic star from the Bay Area paralleled his own — wrote Sunday that the vice president is “Tough. Fearless. Tenacious.”

“With our democracy at stake and our future on the line, no one is better to prosecute the case against Donald Trump’s dark vision and guide our country in a healthier direction than America’s Vice President, @KamalaHarris,” he posted on X.

Harris, a former prosecutor, is a product of the same rough-and-tumble Bay Area politics that produced some of the nation’s most high-profile Democrats, including Newsom, former House Speaker Nancy Pelosi, and former U.S. Sens. Dianne Feinstein and Barbara Boxer.

She has shown tenacity throughout her political rise, from her successful 2003 campaign for San Francisco district attorney — in which she defeated an incumbent Democrat and her former boss — to her failed 2020 presidential campaign, in which she forcefully criticized Biden on the debate stage for his record on desegregation school busing.

Then-Sen. Kamala Harris at an event in Ames, Iowa, in February 2019.

(Marcus Yam / Los Angeles Times)

But she also has been criticized as too cautious and unwilling to take a stand on hot-button issues.

“Her 2020 campaign did not exactly inspire confidence,” said Jim Manley, who spent decades in the Senate as a top leadership aide. “Most disturbingly, when the campaign began to flame out, it was racked by infighting and a massive amount of finger pointing.”

Manley said that while Harris has “got to play her cards absolutely perfect” and do a better job of communicating, “she’s tough enough to pull this off, which is why the Trump folks are getting nervous.”

Harris, born in Oakland in 1964, is the daughter of two immigrant graduate students. Her late mother, Shyamala Gopalan Harris, was a cancer researcher from India; her father, Donald Harris, was an economist from Jamaica.

Harris’ parents divorced when she was 7, and her mother became the primary caretaker and dominant influence for her and her younger sister, Maya.

“There is no title or honor on earth I’ll treasure more than to say I am Shyamala Gopalan Harris’ daughter,” she wrote in her 2019 memoir, “The Truths We Hold: An American Journey.”

After college, she worked as a prosecutor in Alameda County and San Francisco, where she made her first foray into politics when she ran for district attorney and overcame steep odds to defeat Democratic incumbent Terence Hallinan.

During the race, she positioned herself to the right of the progressive D.A., as the law and order candidate. With one exception — she made it clear during the race that she was against the death penalty.

Then-California Atty. Gen. Kamala Harris with Gov. Jerry Brown in 2012.

(Patrick T. Fallon / For The Times)

Four months after Harris was elected, San Francisco police Officer Isaac Espinoza was shot to death by a reputed gang member with an AK-47 while on patrol in the city’s Bayview District. Shortly after Espinoza was killed but before he was buried, Harris said she would not seek the death penalty in the case.

Harris attended the funeral at St. Mary’s Cathedral. So did then-Sen. Feinstein, then-California Atty. Gen. Bill Lockyer and hundreds of police officers. With Harris sitting in a front pew, Feinstein and Lockyer both demanded that the assailant face the death penalty.

“She took an incredible amount of flak,” said Dan Morain, author of the 2021 biography “Kamala’s Way” and a former Times reporter. “I think that that episode made her more cautious in taking public stands on highly controversial matters.”

Years later, as attorney general, Harris worked in court to uphold California’s death penalty despite her personal opposition, putting her at odds with progressive criminal justice reform advocates and fueling perceptions that she was wishy-washy.

But as attorney general, she also gained national attention for refusing to defend Proposition 8, the California ballot measure that outlawed same-sex marriage — a political risk that boosted her political profile and helped pave the way for a massive cultural shift.

In diverse California, and as she moved onto the national Democratic stage, Harris’ multiracial background was a political asset that invited comparisons with former President Obama. Harris created her own multiracial, blended nuclear family when, in 2014, she married Doug Emhoff, a white entertainment lawyer from Los Angeles, and became stepmother to his two children, Cole and Ella, earning the moniker Momala.

Harris campaigns for U.S. Senate in 2016.

(Barbara Davidson / Los Angeles Times)

In November 2016, Harris — endorsed by Obama and Biden — won election to the U.S. Senate, becoming just the second Black woman to do so.

But her decisive victory was eclipsed by the election of Trump, whose defeat of Democrat Hillary Clinton stunned members of both parties. In a speech to her supporters on election night, she said: “When we have been attacked and when our ideals and fundamental ideals are being attacked, do we retreat or do we fight? I say we fight!”

The Trump era gave her even more of a rise to prominence. In the Senate, she brought her skills as a prosecutor to hearings. She grilled conservative Supreme Court nominee Brett M. Kavanaugh with such force that video clips of her performance rocketed across social media as a sort of audition tape for her 2020 presidential run.

Her then-presidential candidacy quickly fell flat as she failed to distinguish herself in a crowded Democratic field and her campaign was hobbled by staff infighting and ill-defined messaging.

Still, she made a dramatic impression during one Democratic debate, attacking Biden for working with Senate segregationists decades ago in opposition to school busing.

“There was a little girl in California who was part of the second class to integrate her public schools. And she was bused to school every day,” she said. “And that little girl was me.”

Harris joins President Biden as he greets former President Obama at a White House event in 2022.

(Kent Nishimura / Los Angeles Times)

When Biden and Harris were elected together the next year, Harris, clad in workout clothes, was filmed as she called to congratulate Biden in what became a viral moment as she said: “We did it, Joe.”

As vice president, Harris was closely watched by the media and fellow Democrats — both because she was a barrier-breaking figure and because of Biden’s advanced age and much-questioned prospects for a second term.

The attention was not all flattering. Critics said early turnover in her staff was a sign of weakness in management style. Supporters said that, as a woman of color, she was the victim of a double standard, scrutinized more than her white male predecessors.

“She gets underestimated. There is more than one layer there,” said Morain, the biographer.

Sen. Laphonza Butler (D-Calif.), who has known Harris for 14 years and served as an advisor in her failed 2020 presidential bid, said she had watched the vice president navigate plenty of political minefields.

“This is a woman who literally works to bring people together,” Butler said. “And even when the critique is about her, she works diligently to find subjects and even concepts in those critiques of her, to bring unity and agreement.”

Times staff writer Faith Pinho contributed to this report.