The mayor of Tallahassee saw off better-funded rivals to become the Democratic nominee and now has his sights on Trump and the Republicans

Not even an early-morning insult from Donald Trump could wipe the smile from Andrew Gillum’s face as he embraced his first full day as the newly elected and rather unexpected Democratic party candidate for Florida governor.

Just hours after sending a lightning bolt to the heart of the Sunshine State’s political establishment with his historic upset victory over bigger-spending rivals, Gillum, the 39-year-old mayor of Tallahassee who is vying to be the first African American in the governor’s mansion, was already campaigning for November’s election.

“Donald Trump and Ron DeSantis are both scraping from the bottom of the barrel,” he said on CNN. He was responding to the US president’s tweet praising Gillum’s freshly minted Republican opponent and blasting the Democrat as “a failed Socialist Mayor… who has allowed crime & many other problems to flourish in his city”.

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Gillum continued: “I actually believe that Florida and its rich diversity are going to be looking for a governor who is going to bring us together, not divide us. Not misogynist, not racist, not bigots, they’re going to be looking for a governor who is going to appeal to our higher aspirations as a state.”

It was a strong statement of unity that has served the progressive liberal well, not only in his run for the nomination, backed by George Soros and Bernie Sanders, but throughout his political career.

As a 23-year-old student at the historically black Florida Agricultural and Mechanical University (Famu), Gillum championed a people-first approach to politics and more funding for education during his successful campaign to be the youngest person ever elected to Tallahassee’s city commission. When in office he pushed forward a number of community- and education-focused projects including providing technology for schools and opening a support and activities center for the city’s vulnerable youth.

Play Video 0:56 Democrat Andrew Gillum speaks after surprise victory in Florida primary – video

During this year’s campaign he spoke often of his working-class roots and being the fifth of seven children born in Miami to a father who was a construction worker and a mother who drove school buses.

“Andrew Gillum has a very engaging personality and he is very clear and strong about his beliefs,” said Christopher Daniels, professor of political science at Famu. “He is a strong advocate for increasing pay for teachers, minimum wage and improving our school systems. These things are all very important [to voters].”

On other issues, Gillum was much further to the left than the rivals he defeated, and more in line with the progressive fringes of the Democratic party now coming to the fore. He has promised to suspend the death penalty in Florida; in July he called for the abolition of Ice, the customs and immigration enforcement agency; and he has been an outspoken critic of the gun lobby, priding himself on his F-rating from the National Rifle Association.

Facebook Twitter Pinterest Andrew Gillum talks with a supporter after speaking to voters and public school teachers at a rally in Miami Gardens in August. Photograph: Brynn Anderson/AP

Gillum also won eight of the 10 counties with Florida’s highest proportion of black residents.

His four-year tenure as Tallahassee mayor, meanwhile, has not come without criticism or controversy, despite earning praise for its focus on education and inclusivity. Despite a recent decrease, Leon county’s crime rate alluded to by Trump is still the highest in the state. And unanswered questions over an FBI investigation into Tallahassee’s community redevelopment agency shadowed his campaign.

But for Gillum himself, it is all about seizing the moment. “My mother said the only thing in life you should ever ask for is a chance,” he said in a pre-election tweet. “This is our chance.”