Lee Jae-myung, the candidate for the opposition Democratic Party, is poised to become South Korea’s next president after provisional results of a snap election showed him on course for a comfortable win.

The election was triggered by former President Yoon Suk-yeol’s short-lived imposition of martial law in December.

The 61-year-old Lee is expected to be sworn in on Wednesday, becoming the country’s 14th president after defeating Kim Moon-soo of the conservative People Power Party (PPP). The South Korean president serves a single five-year term without the possibility of re-election.

The PPP’s Yoon was impeached and removed from office in early April for his martial law debacle. The shock move sparked weeks of protests and investigations and made Yoon South Korea’s shortest-serving president.

Here is what you need to know about Tuesday’s election and its impact:

Who won South Korea’s presidential election?

With 85 percent of the ballots counted, the National Election Commission (NEC) said provisional results showed Lee winning more than 48 percent of the votes with Kim at 42.9 percent.

Although the NEC is yet to formally declare a winner, Kim has conceded defeat and congratulated Lee on his win.

Shortly before Kim’s concession, Lee emerged outside his house in Seoul, where throngs of supporters had gathered. Lee told them he was “highly likely to become the president”.

Nearly 80 percent of the country’s 44.4 million eligible voters cast ballots – the highest turnout since 1997, according to the NEC.

Earlier, exit polls by South Korea’s three major TV stations – KBS, MBC and SBS – projected a comfortable win for Lee. The exit polls projected more than 50 percent of the vote for the opposition candidate and 39 percent for Kim.

Trailing behind them was Lee Jun-seok of the conservative New Reform Party. Analysts said Kim underperformed, hurt by his ties to Yoon and his failure to persuade Lee Jun-seok to unify the right-wing vote. By late on Tuesday, Lee Jun-seok also had conceded defeat.

Who is Lee Jae-myung, South Korea’s new president?

Lee – who served as governor of South Korea’s most populous province, Gyeonggi, and mayor of Seongnam near the capital, Seoul – is a divisive figure. This election marked the human rights lawyer-turned-politician’s third attempt to secure the presidency.

Lee lost the last presidential election to Yoon by the slimmest margin in the country’s democratic history. He went on to lead the Democratic Party to a landslide victory in last year’s legislative elections and was the driving force behind the opposition-led campaign to remove Yoon from office.

During the six-hour martial law period, Lee scaled the National Assembly walls to bypass military blockades, livestreamed his entry and urged citizens to protest. Nearly two-thirds of the lawmakers ultimately made it past the barricades to vote unanimously to end the emergency measures.

Despite his critics calling him a dangerous populist, Lee has promised to pursue pragmatic diplomacy: calling South Korea’s alliance with the United States the foundation of its foreign policy and promising to solidify a Seoul-Washington-Tokyo partnership, a stance that is not much different from the position held by the conservatives.

He has preached patience over US President Donald Trump’s tariff policy, arguing it would be a mistake to rush negotiations in pursuit of an early agreement with Washington.

Lee has also pledged to improve relations with rival North Korea, including reopening dialogue, restoring military hotlines and reviving denuclearisation talks.

The East Asian country’s deep-seated economic inequality is another issue Lee has promised to fix. He has advocated for a four-and-a-half-day workweek in a country known for its demanding work culture.

Lee is facing five ongoing trials related to corruption and other criminal charges. Most of these cases have been delayed until after the election. He denies any wrongdoing and says the charges are politically motivated.

How did Lee win?

Lee capitalised on his role as an opposition member by standing against Yoon’s martial law bid and promising to guide the country out of its political and economic turmoil.

Experts said Yoon also left the PPP in crisis as infighting plagued the party when it tried to choose his successor.

Although Kim won the party primary, PPP leaders tried to replace him with former Prime Minister Han Duck-soo. On the eve of the party’s campaign launch, they cancelled Kim’s candidacy, only to reinstate him after party members opposed the move.

Youngshik Bong, research fellow at Yonsei University in Seoul, said the infighting as well as divisions in the conservative camp over Yoon’s decree cost it support.

“Kim Moon-soo has not set his position clearly on the martial law declaration,” Bong said. “He has not distanced himself from the legacy of Yoon, but at the same time, he has not made it clear whether he believes the declaration of martial law was a violation of the constitution. So the PPP has not really had enough energy to mobilise its support bases.”

What were the key issues in the election?

The botched martial law cast a shadow over the election. It put Lee, after his loss to Yoon in 2022, back on track for the presidency.

“This election would not have happened if not for the declaration of martial law by Yoon Suk-yeol and his impeachment,” Bong said. “These issues have sucked in all others like a vortex. Everything else is marginal.”

On the campaign trail, Lee pledged to bring to justice anyone involved in Yoon’s failed martial law bid and to introduce tighter controls on the president’s ability to declare martial law.

A slowing economy, challenges posed by Trump’s America First policies and worsening ties with North Korea were other topics that mattered to the voters.

What is the significance of Lee’s win? What’s next?

Lee is to take his oath of office on Wednesday morning. The certification process is expected to take no more than 10 minutes.

There’s usually a two-month gap between a presidential election and the winner’s swearing-in, but the recent political turmoil scrapped that plan.