WASHINGTON - Joe Biden selected Senator Kamala Harris of California as his vice-presidential running mate, embracing a former rival who sharply criticized him in the Democratic primaries but emerged after ending her campaign as a vocal supporter of Mr. Biden.

A former rival for the Democratic presidential nomination, she will be the first woman of colour to be nominated for national office by a major political party.

A pragmatic moderate, she is the first Black woman on a major party ticket.

She is a prominent advocate of racial-justice legislation after the killing of George Floyd in late May.

Ms. 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 U.S. history to be chosen for a presidential ticket.

She brings to the race a far more vigorous campaign style than Mr. 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.

The presumptive Democratic presidential nominee to face Donald Trump has described her as a “fearless fighter for the little guy, and one of the country’s finest public servants”.

Ms Harris, 55, was born in Oakland California in 1964 to a Jamaican father and Indian mother who had immigrated to the United States.

She attended Howard University before entering law school at the University of California.

She is also married to a Jewish husband, Douglas Emhoff, and is stepmother to his two children, Cole and Ella.

Ms Harris was elected to the US Senate in 2017 after serving as California’s attorney general 2011, two of the highest state-level offices in the largest state in the country.

Before that, she was elected as district attorney for San Francisco after beginning her career in the Alameda County District Attorney’s Office.

Biden will face President Donald Trump in the election on 3 November.