With 94.4 percent of the votes counted after midnight, Lee won 48.8 percent and his major rival Kim Moon-soo of the conservative People Power Party took 42.0 percent, the National Election Commission data showed.

Even if all the remaining uncounted votes go to Kim, Lee will win the presidential by-election, confirming his victory.

Local broadcaster JTBC and three terrestrial broadcasters including KBS, MBC and SBS forecast earlier that Lee was certain to be elected the country’s 21st president.

Preliminary voter turnout reached 79.4 percent, marking the highest in 28 years since the voting rate recorded 80.7 percent in 1997.

Out of about 44.39 million eligible voters, some 35.24 million cast their ballots at 14,295 polling stations across the country.

The voter turnout, which included those who participated in early voting last Thursday and Friday, was up from 77.1 percent tallied in the previous presidential election in 2022.

Lee Jae-myung and his wife Kim Hye-kyung celebrate at the National Assembly in Seoul, South Korea, on June 4, 2025. Lee Jae-myung of South Korea's majority liberal Democratic Party was elected president, the ongoing vote count by the National Election Commission showed on Wednesday. (Xinhua/Yao Qilin)