(CNN) - Beto O'Rourke raised $6.1 million in the first 24 hours of his presidential campaign, his campaign said Monday, in what amounts to the largest announced first-day haul of any 2020 Democratic contender to date.
The former Texas congressman raised $6,136,763 in online donations from all 50 states on the first day, his campaign said. That tops the $5.9 million one-day total Sen. Bernie Sanders announced after he launched his campaign. The closest other 2020 Democratic candidate to publicize their first-day fundraising total was California Sen. Kamala Harris at $1.5 million.
The first-day total shows O'Rourke has the potential to recreate the record-smashing fundraising prowess he exhibited during his 2018 U.S Senate campaign. A more complete picture of what candidates have raised — and how much they spent, particularly on social media advertisements, to raise that money — will come in April, when reports covering the first fundraising quarter are due.
"In just 24 hours, Americans across this country came together to prove that it is possible to run a true grassroots campaign for president -- a campaign by all of us for all of us that answers not to the PACs, corporations, and special interests but to the people," O'Rourke said in a statement announcing the total.
O'Rourke's haul came after he launched his campaign with a video and several campaign stops Thursday in Iowa.
He began the campaign with big promises, telling reporters in Keokuk, Iowa, that he planned to "run the largest grassroots campaign this country has ever seen."
But until now, there had been little proof of O'Rourke's ability to carry out that plan. His refusal to release first-day fundraising totals over the weekend had raised doubts that O'Rourke had met fundraising expectations around his campaign launch. He remained coy about his fundraising for days.
"I can't right now," he said Friday in Washington, Iowa.
A reporter responded that O'Rourke could share his fundraising totals if he wanted to.
"You're right," he responded. "I choose not to."
Still, a sign that his campaign had begun with a massive fundraising haul came Saturday night when O'Rourke -- who is playing catch-up in hiring staffers as one of the last major Democratic candidates to launch -- told reporters in Dubuque, Iowa, that he would support his campaign unionizing, as Sanders had, and hoped to pay the highest wages and benefits of any presidential contender.
Last year, O'Rourke shattered Senate campaign fundraising records and raised $80 million in his bid to oust Republican Sen. Ted Cruz. His closer-than-expected loss propelled talk of a presidential bid.
He did so with a pledge not to accept money from political action committees, which O'Rourke carried over to his presidential campaign. The approach is unusual -- many other Democratic presidential contenders have sworn off money from corporate PACs, but accept money from those friendlier to Democratic interests, like labor unions. Sen. Elizabeth Warren has also sworn off all PAC money.
O'Rourke emphasized that pledge in a first-day fundraising email.
"Our campaign will be funded by We the People — that is how we'll be able to reach and listen to voters in all 50 states. No PACs. No corporations. No lobbyists or special interests. It'll be ALL people," an email to supporters signed "Team Beto" said.
"If we have a strong showing on our first day, people will see it as a sign that this campaign is off to a good start. That will encourage even more people to join us," O'Rourke said in another fundraising email on the first day.
O'Rourke has also quickly returned to a habit that made him a viral hit in Texas: He is livestreaming most events on Facebook, drawing an audience of thousands to watch him campaign in real time.
O'Rourke began his campaign with a series of smaller events in coffee shops across eastern Iowa, and then in Wisconsin. A small group is operating in El Paso, where he is headquartering his campaign. O'Rourke has not yet hired a campaign manager, though he is in talks with veteran Democratic strategist Jen O'Malley Dillon, who was former President Barack Obama's deputy campaign manager in 2012 and would be seen as a major coup, a source familiar with their discussions said.