MIAMI — Donna Deegan, a Democrat, was elected mayor of Jacksonville on Tuesday, shaking up the politics of Florida’s largest metropolis, the place Republican mayors have been in energy for all however 4 of the final 30 years.

Ms. Deegan, a former tv news anchor, defeated Daniel Davis, a Republican endorsed by Gov. Ron DeSantis, who had been seen because the probably favourite within the historically Republican stronghold. In latest years, Jacksonville had been essentially the most populous metropolis within the nation with a Republican mayor, Lenny Curry, who’s term-limited; that distinction now goes to Fort Worth, Texas.

Ms. Deegan’s victory is a uncommon vibrant spot for Florida Democrats, whose losses have mounted in latest elections to the purpose that the occasion has little sway within the State Capitol and a skinny candidate bench.

But whereas Florida has change into decidedly extra Republican — and whereas many have considered Mr. DeSantis, a possible 2024 presidential contender, as all-powerful in state politics — Jacksonville has emerged as a swingy nook of the state. A majority of voters in Duval County, which shares a consolidated authorities with town of Jacksonville, voted for the Democratic nominee for governor in 2018, for the Republican mayor in 2019, for President Biden in 2020, for Mr. DeSantis final 12 months, and now for Ms. Deegan, who would be the metropolis’s first feminine mayor.

“We made history tonight,” Ms. Deegan instructed cheering supporters Tuesday night time after Mr. Davis conceded.

Ms. Deegan campaigned as a change candidate, leaning into the relationships she had made in the neighborhood as she overcame breast most cancers thrice whereas engaged on tv and as she later created the Donna Foundation, a nonprofit group that helps individuals recognized with breast most cancers.

“I made a decision when we got into this race that, no matter what happened, no matter what the landscape was like, we were going to lead with love over fear,” Ms. Deegan mentioned Tuesday night time. “We would not go with division. We would go with unity.”

Mr. Davis, the chief government of the native chamber of commerce, out-raised Ms. Deegan by a margin of 4 to at least one and appeared just like the type of business-friendly Republican that has lengthy dominated elections in Jacksonville, a Navy and transport city. Mr. Curry, the outgoing mayor, was beforehand the chairman of the Republican Party of Florida.

Mr. Davis was generally known as extra of a reasonable when he was a state lawmaker, and because the chief of JAX Chamber he supported positions comparable to protections for the L.G.B.T.Q. group. But as a mayoral candidate, he campaigned from the political proper, promising to advertise causes espoused by the conservative group Moms for Liberty, which is carefully aligned with Mr. DeSantis. He additionally pledged to be robust on crime in a metropolis that has struggled with stubbornly excessive crime charges for years, together with below Republican management.

In ads, Mr. Davis and different Republicans solid Ms. Deegan as “radical” for backing demonstrators after the homicide of George Floyd in 2020 — although Mr. Curry and different native Republicans additionally supported the protests on the time.

On Tuesday night time, Mr. Davis mentioned he could be prepared to assist Ms. Deegan for the nice of town. “I’m going to do everything I can to make sure Mayor-elect Deegan is successful in making Jacksonville the best Jacksonville it can be,” he mentioned. The metropolis has a strong-mayor type of authorities, giving the mayor broad administrative powers.

Mr. DeSantis, who received Duval County by an 11 percentage-point margin in November, didn’t endorse Mr. Davis till late March — after Mr. Davis had already been forced into Tuesday’s runoff towards Ms. Deegan.

Beyond his lukewarm endorsement, which took place via Twitter on a Friday afternoon, Mr. DeSantis provided Mr. Davis little help. The governor didn’t go to Jacksonville to marketing campaign, unlike considered one of Florida’s different prime Republicans, Senator Rick Scott, who spent final weekend knocking on voters’ doors.

In 2020, Ms. Deegan misplaced a congressional race by 22 share factors. On Wednesday morning, unofficial outcomes showed she had received about 52 % of the vote, in contrast with Mr. Davis’s 48 %, a distinction of about 9,000 votes. Turnout was about 33 %.

Though 39 % of Duval County voters are registered Democrats, in contrast with 35 % registered Republicans and 24 % registered with out occasion affiliation, Republican voters outnumbered Democratic ones by about 3.5 share factors on Tuesday — that means that Ms. Deegan received independents and crossover Republican votes.

Five different Jacksonville Democrats have been elected on Tuesday, one as property appraiser and 4 to the City Council.

Ashley Walker, a political advisor for Ms. Deegan, mentioned that campaigning on native points and with a candidate who linked nicely with voters have been key to flipping Jacksonville from pink to blue.

“Democrats in Florida have to eat the elephant piece by piece,” she mentioned. “We have to go win in these local areas that are purple and get down to the base of some local campaigns to have any chance of coming back statewide.”

Nicholas Nehamas contributed reporting.