Kamala Harris, the barrier-breaking California senator and the state’s former attorney general, has officially launched her presidential campaign for 2020, jumping into an increasingly diverse Democratic field so far dominated by a new generation of women and minority candidates.

Harris, the daughter of immigrants from India and Jamaica, launched her campaign for the White House on Monday – America’s Martin Luther King Jr Day holiday – in an appearance on ABC’s Good Morning America.

“Let’s do this, together. Let’s claim our future. For ourselves, for our children, and for our country,” Harris , 54, said in a campaign video that was released to coincide with her appearance on the morning television show.

The first-term senator portrayed herself as a fighter for justice, decency and equality in the video. “They’re the values we as Americans cherish, and they’re all on the line now,” Harris says. “The future of our country depends on you and millions of others lifting our voices to fight for our American values.”

She will formally launch her campaign on Sunday at a rally in Oakland, California, the city where she was born and where she began her career as a prosector in the Alameda county district attorney’s office.

Harris’s announcement follows the high-profile entrances of her fellow senators Elizabeth Warren of Massachusetts and Kirsten Gillibrand of New York as well as the Hawaii congresswoman Tulsi Gabbard and former housing secretary Juilán Castro.

She may also face competition from several other Senate colleagues who are also weighing presidential bids in a primary race that has no frontrunner, including Cory Booker of New Jersey, Sherrod Brown of Ohio, Amy Klobuchar of Minnesota and Bernie Sanders of Vermont.

The former vice-president Joe Biden, the former Texas congressman Beto O’Rourke and former New York City mayor Michael Bloomberg are also considering runs. So too are home-state politicians including Los Angeles’s mayor, Eric Garcetti, and the California congressman Eric Swalwell.

In the run-up to her campaign launch, Harris traveled the country on a book tour that she used as an opportunity to introduce herself – beginning with how to pronounce her name. “It’s ‘comma’ then add a ‘la’,” she told an audience in Washington, explaining that it means lotus in Sanskrit.

Harris will probably use that mnemonic trick again as she campaigns around the country. A recent NPR/PBS NewsHour/Marist poll found that 54% of a Democratic primary voters were unsure of, or had never heard, of Harris.

In the book, she casts herself as a perfect fit for this political moment. She has a compelling biography that often draws comparisons to Barack Obama mixed with a record – and plenty of viral material – of standing up to Trump on the issues that most inflamed the liberal base, from the travel ban to the Daca program for young undocumented immigrants to the Kavanaugh supreme court nomination.

Harris began her career as a deputy district attorney in Alameda county, California, before becoming district attorney of San Francisco, where she focused on crime prevention. In 2010, she narrowly beat her Republican opponent to become California’s attorney general. Six years later she was easily elected to the Senate, where she became the second black woman ever to serve in the chamber.

Republicans welcomed Harris to the race on Monday, by calling her “unqualified and out-of-touch”.

“Kamala Harris is arguably the least vetted Democrat running for president,” the Republican National Committee spokesman, Michael Ahrens, said in a statement, adding: “All she has to show for her brief time in the Senate is a radically liberal voting record.”

Since arriving in the Senate in 2016, Harris has built a reputation for bringing a prosecutorial style of questioning to hearings with Trump nominees. In a combative exchange with the former attorney general Jeff Sessions, he said her rushed questions were making him “nervous”.

While the skills she honed in the courtroom have served her well in the Senate – and helped to elevate her to the forefront of the anti-Trump resistance movement – progressives have lingering and serious questions about her career as California’s “top cop”.

A recent op-ed published in the New York Times by the University of San Francisco law professor Lara Bazelon accuses the senator of having been “often on the wrong side of history” when she served as the state’s attorney general. She pointed to her support of an initiative that threatened the parents of habitually truant elementary school children with jail time. She also defended a prosecutor who falsified testimony, only relenting after the case attracted national attention.

Harris has highlighted other aspects of her record. She touts Back on Track, a program instituted while she was the DA in San Francisco, which allowed first-time non-violent drug offenders a chance to have their charges dismissed if they completed vocational training. And in her book she recounts a “shouting match” she had over the phone with the JPMorgan Chase boss Jamie Dimon during the foreclosure crisis: “I took off my earrings (the Oakland in me) and picked up the receiver.” It’s an anecdote certain to draw wild applause from anti-Wall Street liberals on the stump.

During the 2018 midterm elections, Harris campaigned on behalf of several women and minority candidates. She is aligned with many of her colleagues and the other contenders on policy, including her support for Medicare-for-All-style healthcare. And like several of the early entrants, Harris has vowed not to accept donations from corporate political action committees, a pledge that is gaining traction among Democratic voters.