Sen. Kamala D. Harris of California will join Joe Biden on the Democratic presidential ticket, Biden announced Tuesday, ending months of speculation about who his running mate would be.

Harris, who is Black and Indian American, will become the first woman of color on a major-party presidential ticket when she and Biden are formally nominated by Democrats at next week’s virtual convention. She will be only the fourth woman on a major-party ticket.

Here’s what you should know about her.

Why Biden picked her

Harris was considered the likeliest pick throughout the search process. She had among the best name recognition of any candidate thought to be on Biden’s shortlist, save for perhaps Sen. Elizabeth Warren (D-Mass.), in part because of her own presidential run. Though Harris did not crack above 20 percentage points in most polls during her campaign, she was well-liked among many demographics in the Democratic Party base, including women and Black voters.

Harris was responsible for the most memorable attack from any of the 2020 Democratic primary debates, when she went after Biden’s support for busing as a senator in the 1970s. That blistering moment was viewed as the biggest barrier to her chances of becoming Biden’s running mate, but Biden’s team sought to play that down. In July, a photograph of Biden’s notes for a news conference included the phrase “do not hold grudges.”

Her background

Harris has represented California in the U.S. Senate since 2017, when she became the second Black woman and the first South Asian American to join the upper chamber. Before that, the Oakland native had been California’s attorney general since 2011.

Harris was born to parents who immigrated to the United States from India and Jamaica to work at universities in the San Francisco Bay area. A graduate of Howard University and the University of California’s Hastings College of the Law, Harris spoke often during her presidential bid about how influential the two universities were in shaping her identity and her views of race and justice in America before preparing her to be a district attorney.

Harris was elected the district attorney of San Francisco in 2003, becoming the first Black district attorney in the state. She is married to lawyer Douglas Emhoff and is stepmother to his two children from a previous marriage.

What she brings to the ticket

Throughout the months leading up to her selection, Harris was seen as one of the most qualified of Biden’s potential picks, and one who would appeal to demands for a diverse ticket. Biden has a strong chance of winning the presidency, and Harris was seen as among the least likely to harm those chances. Her previous run for the top job also means she has dealt with something amounting to the scrutiny that would come with being a VP pick.

Harris, at 55, is more than two decades younger than Biden, who would be the oldest president elected if he won. Biden had faced significant pressure to pick a Black woman, so those voices will probably be pleased by her selection.

While Biden has been tough on President Trump, he has also been less critical of Trump supporters, in part hoping to win their support and not blaming them for their 2016 vote for the Republican. Outside her presidential run, Harris was best known in Washington for applying her prosecutorial skills to grilling Trump nominees during committee hearings, a skill that could be useful in the October debate with Vice President Pence.

The potential downsides

Harris was not a favorite of the left flank of the Democratic Party. In a climate of increased interest in police accountability, her résumé as a prosecutor and California’s attorney general caused concern among people who want to see those with law enforcement backgrounds have a less prominent place in society. While popular with some in the base, Harris is viewed as more of an establishment Democrat. So it’s not clear that she will drive more enthusiasm for Biden from those on the left, such as supporters of Sen. Bernie Sanders (I-Vt.) and Warren.

Trump and his team have had months to gear up for attacking the vice-presidential pick, and they saw Harris as the likely Biden pick, as well. The campaign’s statement about her nomination referenced her debate attack on Biden and called her “Phony Kamala.”

Aaron Blake contributed to this report.