DeSantis has denied accusations of racism first when he warned voters not to "monkey this up" and vote for Gillum.
The outcome of elections for state positions could also affect future control of the U.S. House of Representatives.
In Little Havana, 34-year-old Enrique Tarrio says he chose DeSantis because the businesses he owns have flourished under Republican Gov. Rick Scott.
DeSantis has represented northeast Florida in Congress since 2012.
Voters headed to the polls Tuesday to actually vote in Florida's gubernatorial race.
After casting his ballot on a drizzly morning in Tallahassee, the capital of Florida, Gillum said his election would send a message to Trump "that the politics of hatred and of division, of separation, that they've come to an end".
Another theme struck by DeSantis and his supporters on Monday was an appeal to Hispanic voters. "I'm simply saying the racists believe he's a racist". "I always vote, but ever since Trump was elected, it's felt especially important to participate".
"We all learned in 2016 not to count on anything, not polls, not election integrity, not the electoral mood", Dawn Hucklebridge, 36, a friend of Gillum, said at his election night gathering as it became clear he would likely lose. We can't have that. "I'm concerned about my community - that's why I vote".
The big victor: You guessed it, the Democrat on the ticket, Tallahassee Mayor Andrew Gillum, who managed to secure a victory. Phillis and Jeffrey voted for Andrew Gillum. Trump visited Florida and held a rally with DeSantis on October 31.
Gillum had pulled off an upset in the Democratic primary, winning the nomination after consistently polling in third for most of that race, but he was unable to carry that same momentum into the general election. The same day DeSantis is sworn in, three justices who have been viewed as liberal will retire. Basically it's a swing state in a relatively Democratic year with a Democratic incumbent - it all looked like a real advantage for Nelson. In 2014, Republicans edged Democrats in votes cast before Election Day, while Democrats led two years ago in the presidential election.
Gillum's candidacy was plagued with allegations about his spending while he was mayor of Tallahassee and questions about whether or not an FBI investigation into the city during his tenure as mayor had extended to him.