Opposition leader Lee Jae-myung (center) leaves the Seoul Central District Court in southern Seoul on Friday after the court's sentencing on his election law violation charges. (Yonhap)

Opposition leader Lee Jae-myung was handed a suspended one-year prison sentence Friday for allegedly making false statements during the 2022 presidential campaign -- a ruling that, if upheld, could cost him his parliamentary seat and derail his presidential ambitions.

Lee, chairman of the main opposition Democratic Party of Korea and a prominent likely contender in South Korea’s 2027 presidential race, announced plans to appeal the ruling, saying the court’s conclusions were “not acceptable.”

The Seoul Central District Court delivered its sentence of one year in prison suspended for two years, finding Lee guilty of making false statements in violation of the Public Official Election Act.

The court stated, "Making false statements to voters during the election process can distort and damage public opinion, making the crime particularly serious."

"The offenses in this case were committed under the guise of clarifying suspicions directed at the defendant. By utilizing broadcast media, the impact was substantial," the court added.

Under the Public Official Election Act, if Lee's suspended sentence is upheld, he will lose his parliamentary seat and be barred from running for office for the next 10 years, making a presidential bid impossible.

The Democratic Party also will have to return the 43.4 billion won ($31 million) in election expenses for which it was reimbursed by the National Election Commission in the last presidential election.

Lee was found guilty of falsely claiming during a parliamentary audit of the Gyeonggi provincial government in October 2021 that the decision to rezone a green belt area so it could be used in a residential development project in Seongnam's Baekhyeon-dong district in the mid-2010s was the result of coercion by the Land Ministry.

The court ruled that this claim constituted a false statement and the dissemination of false information, stating, "It appears that Lee reviewed and decided on the rezoning of Baekhyeon-dong independently rather than being compelled by the demands of the Land Ministry."

The site was later developed into apartment complexes by a private developer, and allegations were raised that Lee rezoned the land to give preferential treatment to the company.

The court further noted, "The responsible officials in Seongnam City testified that there was no pressure or threats, or that they did not remember any. Therefore, it cannot be considered that the Land Ministry coerced them. Lee's statements regarding Baekhyeon-dong are judged to be false."

However, Lee was found not guilty of making false statements during a December 2021 television interview in which he claimed he did not know the late Kim Moon-ki, an official with an alleged role in a separate scandal.

The court ruled that "Lee's statement that he 'did not know Kim Moon-ki’ is indeed false, but it is difficult to consider it the dissemination of false information."

Kim was a senior official at a state-run company overseeing land development in Daejang-dong, Gyeonggi Province, during Lee’s tenure as mayor of Seongnam. The Daejang-dong development project, led by Seongnam Development Corp., became the center of major controversy.

Allegations surfaced during the 2022 presidential race that the Seongnam city government granted favors to a private developer, enabling them to secure the lucrative Daejang-dong apartment project and reap substantial profits. In December 2021, amid an ongoing investigation, Kim was found dead in his office, intensifying the suspicions surrounding the project and Lee's involvement.

After the trial, Lee told reporters, "The conclusion is not acceptable, even in its basic recognition of facts," and added, "I will appeal."

"The court of public sentiment and history is eternal. If the people make their judgment based on common sense and justice, I believe the conclusion is an easy one," Lee said, underscoring that "There are still two more rounds left in the courtroom."

As the first of four legal battles Lee is currently facing, this trial's outcome is considered particularly significant, with the potential to impact his own political leadership and shape the broader political landscape in South Korea.

The chair of the ruling People Power Party, Han Dong-hoon said on Friday, “We respect and commend the judiciary’s decision, which was made in accordance with the law,” adding, “The People Power Party will stand with the people to uphold the independence and fairness of the judiciary.”

In a statement, PPP chief spokesperson Shin Dong-wook said, "Justice has prevailed."