A LEFT-WING millennial who rose to prominence during anti-government protests has been elected as Chile’s next president, after a bruising campaign against a far-right candidate likened to former US president Donald Trump.

With 56% of the votes, Gabriel Boric defeated opponent Jose Antonio Kast by more than 10 points.

Kast had tried unsuccessfully to scare voters that Boric would upend Chile’s vaunted record as Latin America’s most stable, advanced economy.

Kast immediately recognised defeat, tweeting a photo of himself on the phone with his opponent congratulating him on his “grand triumph”.

He then later travelled personally to Boric’s campaign headquarters to meet with his rival.

Meanwhile, outgoing president Sebastian Pinera — a conservative billionaire — held a video conference with Boric to offer his government’s full support during the three-month transition.

“I am going to be the president of all Chileans,” Boric said in the brief televised appearance with Pinera.

In Santiago’s subway, where a fare hike in 2019 triggered a wave of nationwide protests that exposed the shortcomings of Chile’s free market model, young supporters of Boric, some of them waving flags emblazoned with the candidate’s name, jumped and shouted in unison as they headed downtown to join thousands who gathered for the president-elect’s victory speech.

“This is a historic day,” said Boris Soto, a teacher. “We’ve defeated not only fascism, and the right wing, but also fear.”

Boric’s victory is likely to be felt throughout Latin America, where ideological divisions have been on the rise amid the pandemic.

At 35, Boric will become Chile’s youngest modern president when he takes office in March and only the second millennial to lead in Latin America, after El Salvador’s Nayib Bukele.

He was among several activists elected to Congress in 2014 after leading protests for higher quality education.

He has vowed to “bury” the neoliberal economic model left by general Augusto Pinochet’s 1973-1990 dictatorship and raise taxes on the “super rich” to expand social services, fight inequality and boost protections of the environment.

Kast, who has a history of defending Chile’s past military dictatorship, finished ahead of Boric by two points in the first round of voting last month but failed to secure a majority of votes, setting up a head-to-head runoff between the two.

Boric was able to reverse the difference by a larger margin than pre-election opinion polls forecast by expanding beyond his base in the capital, Santiago, and attracting voters in rural areas who do not side with political extremes.

An additional 1.2 million Chileans cast ballots on Sunday compared to the first round, raising turnout to nearly 56%, the highest since voting stopped being mandatory in 2012.

“It’s impossible not to be impressed by the historic turnout, the willingness of Kast to concede and congratulate his opponent even before final results were in, and the generous words of President Pinera,” said Cynthia Arnson, head of the Latin America program at the Wilson Centre in Washington.

“Chilean democracy won today, for sure.”

Kast (55) a devout Roman Catholic and father of nine, emerged from the far-right fringe after having won less than 8% of the vote in 2017.

An admirer of Brazil’s far-right president Jair Bolsonaro, he rose steadily in the polls this time with a divisive discourse emphasising conservative family values and playing on Chileans’ fears that a surge in migration — from Haiti and Venezuela — is driving crime.

As a lawmaker he has a record of attacking Chile’s LGBTQ community and advocating more restrictive abortion laws.

In recent days, both candidates tried to veer toward the centre.

“I’m not an extremist … I don’t feel far right,” Kast proclaimed in the final stretch even as he was dogged by revelations that his German-born father had been a card-carrying member of Adolf Hitler’s Nazi party.

But while Kast made a lightning trip to Washington, where he met with Republican senator Marco Rubio, Boric sewed together a broader coalition with more traditional leftist parties, added centrist advisers and promised that any changes would be gradual and fiscally responsible.

Boric’s victory is likely to be tempered by a divided congress.

In addition, the political rules could soon change because a newly elected convention is rewriting the country’s Pinochet-era constitution.

The convention — the nation’s most powerful elected institution — could in theory call for new presidential elections when it concludes its work next year and if the new charter is ratified in a plebiscite.