Pete Buttigieg, the latest Democrat to launch a full-fledged 2020 presidential campaign, raised $1 million just hours after announcing his official bid, according to his spokeswoman.

The fundraising haul, shared Sunday by Buttigieg's team after his announcement speech, provides the latest data point indicating the South Bend, Indiana, mayor's growing profile on the national stage in the few months since entering the contest as a relative unknown.

In the 24 hours after launching an exploratory committee in late January, for instance, Buttigieg raised about $120,000, according to spokeswoman Lis Smith. But after his campaign launch Sunday, Buttigieg collected seven figures in donations in about four hours, the campaign said.

Lis Smith TWEET

Buttigieg, the youngest of the 18-plus confirmed candidates to join the race against President Donald Trump, had already reported raising over $7 million in the first fundraising quarter during his "exploratory" campaign phase. That sum put the 37-year-old mayor ahead of a number of more nationally established candidates for the quarter.

Neither Buttigieg nor any other 2020 Democrat has come close to matching the Trump campaign's first-quarter fundraising haul, however. The president's reelection campaign announced Monday that it took in $30.3 million overall in the fundraising period, leaving it with $40.8 million in cash on hand.

Trump's campaign and the Republican National Committee reported a combined $76.1 million to the FEC.

Buttigieg has used his campaign funds more sparingly, according to a recent filing from the Federal Election Commission. Of the $7,091,224.39 Buttigieg reported raising, he spent less than $700,000. That leaves him with more than $6.4 million in cash on hand, even before adding in the latest $1 million reported by his campaign on Sunday.

That's an especially low "burn rate," experts and media figures have claimed, and one that his spokeswoman chalks up to the self-described millennial mayor's intent to run a "21st century campaign doing more with less."

Claybourn TWEET Pete Buttigieg spent less than $700,000 in Q1 and has $6.4 million in the bank, per new FEC filing. His "burn rate" is less than 10%. Compare that to Gillibrand's 80% burn rate.

Buttigieg told CNBC in a February interview that "I understand this is an underdog project." Yet the Rhodes Scholar and Afghanistan War veteran, who would be both the youngest and the first openly gay president in U.S. history if elected, has matched his fundraising gains with sizable jumps in polling since launching his exploratory committee.

A Emerson national poll of the 2020 contenders in mid-February, for instance, notched Buttigieg at 0% support, falling well below 12 other Democrats in the primary at the time.

But the latest national poll from Emerson released Monday morning saw Buttigieg rise to the No. 3 slot with 9%, beating 17 other Democrats and falling behind only former Vice President Joe Biden and Vermont Sen. Bernie Sanders — both of whom have been leading names in American politics for years.