Her prosecutorial background has been a flashpoint

Before she was elected to the Senate in 2016, Harris spent 26 years as a prosecutor in her home state of California, rising through the ranks to become district attorney in San Francisco before being elected state attorney general in 2010.

But her lengthy prosecutorial record is both one of her most prominent credentials and the source of distrust among liberals who scoffed at Harris identifying herself as a “progressive prosecutor.”

Since the campaign, however, Harris has emerged as one of the leading voices in Congress on criminal justice reform, co-authoring Democrats’ sweeping police reform legislation earlier this summer in the wake of national protests over police brutality.

Harris’ selection marks a rebound after a stinging debate attack

Harris lobbed one of the most forceful attacks of the primary at Biden when she went after his record on school desegregation and busing, as well as his warm words for segregationists in Congress.

In the immediate aftermath of the viral exchange, it appeared to propel Harris to the front of the crowded primary field, though the political boost was ultimately short-lived when Harris acknowledged she had essentially held the same view on busing as he did. The attack also made her the target of backlash from Biden’s allies — and as recently as March, Biden’s wife Jill described the moment as “a punch to the gut.”

But Harris has been a loyal Biden surrogate since she endorsed him back in March, hosting fundraisers and roundtables with the vice president and his wife and defending him on television.

She was close with Biden’s late son

The senator formed a close relationship with Biden’s late son, Beau, when he served as the Delaware attorney general while Harris was attorney general of California. In her 2019 memoir, Harris called Beau Biden, who died of brain cancer in 2015, an "incredible friend and colleague," and wrote that she sometimes spoke with the younger Biden as many as multiple times a day in difficult moments.

Biden and his allies have cited Harris’ friendship with Beau as a key reason her debate broadside stung as much as it did.

“I wasn’t prepared for the person coming after me the way she came after me. She knew Beau, she knows me,” Biden told CNN last year.

“Our son, Beau, spoke so highly of her and you know, and how great she was,” Jill Biden said at the same fundraiser where she lamented Harris’ debate blow.

Not long before the debate moment, Harris had marked the fourth anniversary of Beau’s death on Twitter, writing: “I still miss him.”

Harris is the daughter of immigrants

Her mother Shyamala was the daughter of an Indian diplomat and worked as a cancer researcher, while Harris’ father Donald was born in Jamaica and taught economics at Stanford. The pair met during civil rights protests at UC Berkeley in the 1960s. They divorced when Harris was 7, and Harris and her sister Maya were raised by their mother, whom the senator has cited as a foundational influence in her life.

She made a name for herself with relentless cross examinations of Trump officials

Once she arrived in the Senate in 2017, Harris wasted no time raising her national profile, going viral for her grillings of White House appointees from former Attorney General Jeff Sessions, to Supreme Court Justice Brett Kavanaugh and Attorney General William Barr, to CIA Director Gina Haspel.

In May, Harris campaign surrogate Bakari Sellers posited that Harris’ elite interrogation skills would be put to good use on a Biden ticket.

“What I would take from that for choosing a vice president is she’s a really skilled debater,” he said of her debate confrontation with Biden, “and she’d kick Mike Pence’s ass.”