WASHINGTON — Sen. Kamala Harris (D-Calif.) launched her presidential campaign on Monday with an online video and an appearance on “Good Morning America” in which she said that “this is a moment in time that I feel a sense of responsibility to stand up and fight for the best of who we are.”

Harris, 54, will hold an announcement rally in Oakland on Jan. 27, but her first campaign trip will be on Friday, when she will appear at the Alpha Kappa Alpha Pink Ice Gala in Columbia, S.C. She will visit Iowa on Jan. 28, when CNN will host a town hall there.

In recent weeks she has been building up to an announcement with a new book, including appearances on shows such as “The Late Show with Stephen Colbert.” She also has been contacting donors to line up potential support.

Her announcement video features snappy, upbeat music, flashing words like “truth,” “justice” and “decency,” and warning that cherished American values are “all on the line now.”

“The future of our country depends on you and millions or others, lifting our voices to fight for our American values,” she says.

Before her first term as a U.S. senator, Harris previously served as California’s attorney general and, prior to that, as district attorney of San Francisco. During Barack Obama’s 2008 presidential campaign, she served as a surrogate speaker, and was even then considered a rising figure within the party.

On “Good Morning America,” she focused on her years spent as a prosecutor.

“My entire career has been focused on keeping people safe,” Harris said. “It is one of the things that motivates me more than anything else. And when I look at this moment in time, I know that the American people deserve to have someone who is going to fight for them, who is going to see them, who is going to care about them, who will be concerned about their experience, and put them in front of self-interest.”

Harris is the first African American senator from California and joins a field vying to become the first woman elected to the White House. She is the third female Democrat to enter the 2020 presidential race following Sen. Elizabeth Warren (D-Mass.) and Sen. Kirsten Gillibrand (D-N.Y.). Sen. Amy Klobuchar (D-Minn.) also is considering a presidential bid, and Rep. Tulsi Gabbard (D-Hawaii) said that she plans to run.

But the field is likely to expand in coming weeks. Julian Castro, the former Secretary of Housing and Urban Development, also launched a bid. John Delaney, a former congressman from Maryland, announced in 2017 that he was running.

Although Harris has been focused on building her name recognition, she already has a substantial network of donors from the entertainment industry, for her past Senate and attorney general races as well as her leadership PAC, Fearless for the People. In the most recent cycle, the PAC drew contributions from Ziffren Brittenham attorney Matthew Johnson, CAA’s Richard Lovett, Jeffrey Katzenberg, Universal’s Donna Langley and Sean Hayes, among others. It’s expected that many donors will wait for a bit until endorsing candidates, or make contributions to multiple campaigns, to see how the race shakes out. Harris said that she will not accept money from corporate PACs.

Harris also may be one of a number of Californians to join the race. Los Angeles Mayor Eric Garcetti and Rep. Eric Swalwell (D-Calif.) also are considering presidential bids.