Yoon Suk Yeol received a life prison sentence for rebellion over his short-lived martial law decree in December 2024.
The court convicted him of illegally mobilising forces to seize the National Assembly and arrest politicians.
A special prosecutor sought the death penalty, but no executions have occurred in South Korea since 1997.
Former South Korean president Yoon Suk Yeol has been sentenced to life imprisonment for imposing martial law in a failed bid to consolidate power.
According to AP, the Seoul Central District Court handed down the verdict on Yoon, convicting him of rebellion over the December 2024 decree that lasted just six hours before lawmakers voted unanimously to overturn it.
Judge Jee Kui-youn said he found Yoon guilty of rebellion for mobilising military and police forces in an illegal attempt to seize the liberal-led National Assembly, arrest politicians and establish unchecked power for a “considerable” time.
Yoon, who is likely to appeal the verdict, defended his actions as necessary to counter liberals, whom he described as “anti-state” forces obstructing his agenda with their legislative majority.
A special prosecutor had sought the death penalty, arguing Yoon's moves threatened the nation's democracy and warranted the harshest punishment, but analysts anticipated a life term given the poorly planned power grab caused no casualties.
South Korea has not executed a death row inmate since 1997, maintaining what is seen as a de facto moratorium on capital punishment amid calls for its abolition.
AP reported that as Yoon arrived at court, hundreds of police officers monitored the scene while his supporters rallied outside the judicial complex, their chants audible as the prison bus passed. Nearby, critics demanded the death penalty.
The court also sentenced several former officials involved in the martial law enforcement, including ex-defence minister Kim Yong Hyun, who received a 30-year jail term for his key role in planning and mobilising the military.
Yoon was suspended from office on 14 December 2024 after impeachment by lawmakers, formally removed by the Constitutional Court in April 2025, and arrested last July amid multiple criminal trials, with the rebellion charge carrying the severest penalty.
Last month, Yoon was sentenced to five years in prison for resisting arrest, fabricating the martial law proclamation and bypassing a required full Cabinet meeting before issuing the decree.
Reported AP, the court has convicted two of Yoon's Cabinet members in related cases, including prime minister Han Duck-soo, who got a 23-year prison sentence for trying to legitimise the decree by forcing it through a Cabinet Council meeting, falsifying records and lying under oath. Han has appealed the verdict.
The events unfolded in Seoul, South Korea, in December 2024.
(With inputs from AP)
