Joe Biden selected Senator Kamala Harris of California as his vice-presidential running mate on Tuesday, embracing a former rival who sharply criticised him in the Democratic primaries but emerged after ending her campaign as a vocal supporter of Biden and a prominent advocate of racial-justice legislation after the death of George Floyd in late May.

Harris, 55, is the first Black woman and the first person of Indian descent to be nominated for national office by a major party, and only the fourth woman in history to be chosen for one of their presidential tickets. She brings to the race a far more vigorous campaign style than Biden’s, including a gift for capturing moments of raw political electricity on the debate stage and elsewhere, and a personal identity and family story that many find inspiring.

Biden announced the selection over text message and in a follow-up email to supporters: “Joe Biden here. Big news: I’ve chosen Kamala Harris as my running mate. Together, with you, we’re going to beat Trump.” The two are expected to appear together in Wilmington, Delaware, on Wednesday.

After her own presidential bid disintegrated last year, many Democrats regarded Harris as all but certain to attempt another run for the White House in the future. By choosing her as his political partner, Biden may well be anointing her as the de facto leader of the party in four or eight years.

A pragmatic moderate who spent most of her career as a prosecutor, Harris was seen throughout the vice-presidential search as among the safest choices available to Biden. She has been a reliable ally of the Democratic establishment, with flexible policy priorities that largely mirror Biden’s, and her supporters argued that she could reinforce Biden’s appeal to Black voters and women without stirring particularly vehement opposition on the right or left.

Harris has been regarded as a rising figure in Democratic politics since around the turn of the century, and as a confident representative of the country’s multiracial future.

She is the daughter of two immigrant academics, an Indian American mother and a father from Jamaica. Harris was raised in Oakland and Berkeley, attended Howard University and pursued a career in criminal justice before becoming only the second Black woman elected to the Senate.