Mark Makela/Getty Images; Robin L Marshall/Getty Images Former Vice President Joe Biden, Sen. Kamala Harris
"@JoeBiden can unify the American people because he's spent his life fighting for us. And as president, he'll build an America that lives up to our ideals," Harris, 55, tweeted on Tuesday in the wake of the announcement.
"I'm honored to join him as our party's nominee for Vice President, and do what it takes to make him our Commander-in-Chief," she added.
Harris is the first Black woman and first Indian-American on either major party's presidential ticket.
She is the fourth woman on a major presidential ticket, after Democratic vice presidential nominee Geraldine Ferraro in 1984, Republican vice presidential nominee Sarah Palin in 2008 and Democratic presidential nominee Hillary Clinton in 2016.
Biden, 77, announced his pick for running mate on Twitter Tuesday, writing, "I have the great honor to announce that I’ve picked @KamalaHarris — a fearless fighter for the little guy, and one of the country’s finest public servants — as my running mate."
Matt Baron/Shutterstock Joe Biden and Kamala Harris on July 31, 2019
Minutes after the announcement, Harris received an immediate outpouring of support from other candidates who were reportedly considered by the Biden campaign.
Rep. Karen Bass tweeted that Harris was a “great choice” and wrote the California senator’s “tenacious pursuit of justice and relentless advocacy for the people is what is needed right now.”
Susan Rice, who many speculated to be a top contender for the ticket alongside Harris, shared her “warmest congratulations” for Biden’s new running mate in a statement. “Senator Harris is a tenacious and trailblazing leader who will make a great partner on the campaign trail,” she wrote. “I am confident that Biden-Harris will prove to be a winning ticket," Rice added.
Stacey Abrams, who publicly made her case to be Biden’s running mate throughout the summer, said she’s “thrilled to support” the Biden-Harris ticket.
Michigan Gov. Gretchen Whitmer tweeted that she’s “extraordinarily proud to support” Harris and Biden, referencing the Biden campaign slogan in saying: “They will be a fierce team to Build America Back Better.”
Maya Harris/Twitter From left: former Vice President Joe Biden and Sen. Kamala Harris
A former prosecutor, Harris previously challenged Biden for the Democratic nomination with her own presidential bid last year. While she saw a brief polling surge last July, her momentum withered and she left the race in December, citing a lack of funds.
Harris endorsed Biden in March, weeks before the novel coronavirus pandemic caused mass shutdowns across the United States.
She was one of PEOPLE's Women Changing the World in 2019 — a group of women changing American politics and the way we view the political landscape in the U.S. — alongside fellow senators and former democratic presidential candidates Elizabeth Warren and Amy Klobuchar.
“I think it’s really important for America to just have further evidence of the breadth and depth of what women are and what we can do," Harris told PEOPLE then.
“Each woman who breaks a barrier and expands the minds of people in terms of what’s possible and what that looks like, they do our country a great service,” Harris added. “I certainly do think about it that way.”