LAWRENCE, Mass. — Senator Elizabeth Warren of Massachusetts formally announced her 2020 presidential bid Saturday, calling for “fundamental change” on behalf of working people and arguing that President Trump is “just the latest and most extreme symptom of what’s gone wrong in America.”

Speaking on a clear, chilly day against a backdrop of old red brick mill buildings at the site of one of the nation’s most famous labor strikes, she said workers now, like workers then, had had enough. She said that replacing Mr. Trump, whose administration she called “the most corrupt in living memory,” was only the first step in fighting back against a system tilted in favor of the wealthy.

“It won’t be enough to just undo the terrible acts of this administration,” Ms. Warren said. “We can’t afford to just tinker around the edges — a tax credit here, a regulation there. Our fight is for big, structural change.”

The selection of Lawrence was symbolic: In 1912, a historic labor strike was started by a group of women at Everett Mill, where Ms. Warren made her announcement. The senator drew on the strike as a story of women, many of them immigrants, taking on a stacked system and triumphing by gaining raises, overtime and other benefits.

Ms. Warren described the American economy as similarly tilted against the middle class, with wealth and political power concentrated at the top.

“Today, millions and millions and millions of American families are also struggling to survive in a system that’s been rigged, rigged by the wealthy and the well-connected,” Ms. Warren said. She added: “Like the women of Lawrence, we are here to say enough is enough!”

Ms. Warren, 69, who took the stage to the Dolly Parton song “9-to-5,” described her own journey, growing up as the daughter of a janitor and going on to become a law professor and a senator. As a scholar of bankruptcy law, she explained, she had studied how the opportunities she was afforded had narrowed in recent decades, as the rich became richer and the middle class was squeezed.

She said that the current rising generation of young people could be the first in which a majority were worse off economically than their parents, while the rich “seem to break the rules and pay no price.” In response, the crowd began to shout, “Enough is enough!”

When they quieted, Ms. Warren said, “When I talk about this, some rich guys scream, ‘Class warfare!’ Well, let me tell you something: These same rich guys have been waging class warfare against hard-working people for decades. I say it’s time to fight back!”