U.S. Rep. Ron DeSantis said Friday that he's running for Florida governor, boosted by billionaire backers and an endorsement by President Donald Trump that should make him an immediate contender in the race.

DeSantis, a 39-year-old three-term congressman, made the announcement in typical fashion for him of late: on Fox News.

"With the support of the president, I'm in a position to exercise the leadership that can build on the great work Rick Scott has done," DeSantis said on Fox News' Fox & Friends Friday morning.

The former Navy lawyer has made a name for himself over the last year attacking special counsel Robert Mueller's investigation into Russian meddling in the 2016 election.

And his public support for Trump, often on Fox News, apparently paid off last month, when Trump tweeted that DeSantis was a "brilliant young leader" who would "make a GREAT Governor of Florida."

DeSantis' run was widely expected, and fear over his potential war chest has forced his potential gubernatorial opponents to remind voters of their conservative bonafides.

Just last week, DeSantis boasted an impressive list of billionaire backers, including Las Vegas casino magnate Sheldon Adelson and Breitbart co-owner Rebekah Mercer. David Bossie, the president of Citizens United and Trump's deputy campaign manager in 2016, is also among the backers.

That support will make him a formidable opponent to the current Republican front-runner, Agriculture Commissioner Adam Putnam, and likely candidate Richard Corcoran, the Florida House speaker who has yet to declare.

But DeSantis' opponents were quick to attack him over his perceived grandstanding on national television.

Putnam's campaign compared his own announcement for governor – in front of supporters in his hometown of Bartow – to DeSantis' announcement on Fox & Friends.

"Washington insider Ron DeSantis wore a freshly pressed and tailored suit in an empty television studio this morning to inform broadcasters in New York of his intent to seek a promotion," the campaign said in an email.

Democratic candidate Gwen Graham, a one-term congresswoman and the daughter of former Gov. Bob Graham, called him "out of touch."

"While Ron DeSantis has dedicated himself to protecting Trump and becoming a Fox News star, we look forward to a debate on the issues that affect Florida families," she said on Twitter.

DeSantis was accomplished but little-known in Florida and the national stage before becoming a Fox News darling.

Born in Jacksonville, he earned a history degree from Yale University, where he was captain of the baseball team. He then received a law degree from Harvard University and joined the U.S. Navy as a judge advocate general prosecutor in 2005.

His tour in Iraq was as an advisor to a U.S. Navy SEAL commander, and he's now in the Navy Reserve.

On his first campaign for office, to Florida's conservative 6th congressional district, which stretches from just south of Jacksonville down the northeast coast, he defeated several Republicans with the help of an endorsement by the controversial Arizona Sheriff Joe Arpaio.

Arpaio liked DeSantis because he promised to get tough on immigration, according to the Associated Press. Last year, Trump pardoned Arpaio's criminal contempt of court conviction.

He took office on Jan. 3, 2013, and 18 days later he was on Greta Van Susteren's show on Fox News criticizing Obamacare.

Since then, his tenure in Congress has been notable for being a favorite guest on conservative media and for being a conservative member of the Freedom Caucus that helped drive House Speaker John Boehner into retirement.

He has consistently followed Trump's lead, like when he and U.S. Sen. Ted Cruz, R-Texas, proposed a constitutional amendment in 2016 that would impose term limits on members of Congress – after Trump endorsed the idea.

Not until recently has he become a vaguely household name, when he began going on Fox News and criticizing the Mueller probe. In August, he made national news after proposing legislation that would have cut off funding for the probe after six months.

Taylor Budowich, a spokesman for Watchdog PAC, Corcoran's political committee, said the speaker was focusing on the 2018 legislative session, which begins Tuesday.

"Speaker Corcoran has said he will make his intentions known after the legislative session completes in March," Budowich said. "But looking at the current field right now, it's lacking someone with Speaker Corcoran's long record of conservative accomplishments. … The race is wide open."