DeSantis' win was a crushing blow for Democrats, who had pinned their hopes on Gillum making history as the state's first black chief-of-state and recapturing the governor's mansion for the first time in almost a quarter of a century.
In another closely watched statewide race, Democrat Bill Nelson and Republican Rick Scott were separated by less than 60,000 votes out of a total of more than 8 million as of 1:15 a.m.in their Senate race.
"I want to encourage you not to give up", Gillum, the 39-year-old mayor of Tallahassee, told supporters at his election night party, where small groups of people embraced, tears streaming down their faces. He also reminded voters that the next governor will appoint three justices.
But the Republican defended himself and his supporters against the racist label, while slamming his Democratic opponent for backing a major tax-hike proposal and wanting to expand government programs, including health care.
Meanwhile, President Donald Trump rallied support for DeSantis this past week in Fort Myers and Pensacola, telling voters they had a choice "between greatness and gridlock".
"Republicans had a very strong candidate Adam Putnam, who is in the primary against DeSantis..." In the months leading up to the election, Gillum was projected to win the gubernatorial bid.
Gillum - the mayor of Tallahassee who has the charisma and political acumen that led many to believe he would be the one to finally retake the Florida governorship for the Democrats - came into Tuesday's election soaring high by most pollsters' calculations.More news: Mauricio Pochettino is without a number of players for PSV clash
In Oklahoma, Republican Kevin Stitt defeated Democrat Drew Edmondson, dashing Democratic hopes that outgoing Republican Governor Mary Fallin's low approval numbers had provided a rare opportunity in a deeply conservative state.
"We'll worry about history later but today, we're working to win".
During his victory speech, DeSantis also acknowledged Trump's role in the campaign.
Accusations of race-baiting dogged Kemp, 55, and DeSantis, 40, who denied the allegations.
The former GOP congressman spent weeks explaining the remark, maintaining it had nothing to do with race, but rather his belief that Gillum would hurt Florida's economy.
In the governor's race, former U.S. Rep.
More people in Broward voted for the state's commissioner of agriculture, chief financial officer and attorney general positions than they did for the Senate, according to the preliminary county results. With 99% reporting, Nelson earned 4,039,498 votes - over 42,000 more votes than Gillum.