Ms Warren delivered a call for change at her presidential kickoff, decrying a "middle-class squeeze" that has left Americans crunched with "too little accountability for the rich, too little opportunity for everyone else".
Warren, a former law professor at Harvard University specializing in bankruptcy and commercial law, was a key architect of Barack Obama-era regulations to protect consumers from predatory lenders.
"When I talk about this, some rich guys scream 'class warfare!' " Warren said.
Warren's announcement will be followed on Sunday by U.S. Senator Amy Klobuchar, who has said she will reveal her presidential plans in her home state of Minnesota.
In short, Warren called on her supporters to help her build "an America that works for everyone".
She has been forced to apologise for claiming on several occasions in her early political career that she was of Native American descent.
But it is the story of Warren's family that also had the 2020 candidate facing fresh questions about her credibility this week.
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One thing she didn't mention, though, was her claims of Native American ancestry, which first came to the fore during her 2012 victory over then-Republican Sen. "I want a candidate who will win".
The enmity between the two politicians is no secret, but Warren focused on emphasizing the policies she wanted to enact rather than criticizing those now in use. After proposing an "ultra-millionaire tax" that would hit the wealthiest 75,000 households in America, Ms Warren told Bloomberg News last week that she continued to "believe in capitalism" but wanted to see stricter rules to prevent gaming the system - a marked contrast with the self-described democratic socialism of Sanders.
"Today Elizabeth Warren, sometimes referred to by me as Pocahontas, joined the race for President", Trump wrote early Saturday evening."Will she run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore?"
While Warren represents MA, she was born and raised in Oklahoma, attended college in New Jersey, and taught at law schools in Texas and Pennsylvania before teaching at Harvard.
Since launching her exploratory committee, Warren has traveled to Iowa, New Hampshire, South Carolina and Puerto Rico to meet with voters and test out her 2020 message.
However, when all is said and done, almost two dozen Democrats are expected to enter the fray, with others like Vermont Senator Bernie Sanders, former Vice President Joe Biden, Ohio Senator Sherrod Brown, Oregon Senator Jeff Merkley, California Congressman Eric Swalwell and former Texas Congressman Beto O'Rourke having signaled they're considering a run.
She also backed a constitutional amendment to ensure the right to vote, and she advocated for tightening ethics requirements on members of Congress and even Supreme Court justices.