A South Korean court has sentenced former President Yoon Suk Yeol to life imprisonment after finding him guilty of insurrection for his role in imposing martial law in December 2024 in a bid to seize control of government institutions and block the opposition-controlled National Assembly, judicial officials say.

The verdict delivered on Thursday by the Seoul Central District Court followed months of legal proceedings into one of the most dramatic political crises in South Korea’s recent history. The court concluded that Yoon’s declaration of martial law and deployment of military and police forces aimed to paralyse the legislature and undermine democratic governance.

Judge Jee Kui-youn said prosecutors had proven that Yoon’s actions met the legal standard for insurrection under Korean law and posed a serious threat to constitutional order. Prosecutors had sought the death penalty for Yoon saying his conduct was a grave violation of democratic principles but the court opted for life imprisonment instead.

Yoon was suspended from office in December 2024 after lawmakers moved to overturn the martial law decree and impeached him. The Constitutional Court removed him from the presidency in April 2025, opening the way for criminal prosecutions, and he has been in detention since July 2025 while facing multiple related charges.

In addition to Yoon’s sentence, several former senior officials involved in the martial law declaration and its enforcement have also received prison terms. Among them is former Defence Minister Kim Yong-hyun, who was handed a lengthy sentence for his role in planning and executing the illegal measures.

Yoon’s legal team has signalled plans to appeal the conviction, maintaining that his actions were meant to address what he described as political obstruction even though critics argued his move was an attempt to consolidate power unlawfully.

The case underlines the strength of South Korea’s judicial system and its commitment to upholding the rule of law even when high-ranking political figures are involved in constitutional crises.