Yoon Suk Yeol's life sentence for insurrection "offers a rare example of democratic resilience", experts say.
Yoon Suk Yeol's December 2024 martial law bid fundamentally damaged South Korea's democracy, a judge told the court.
Yoon still faces two trials over his botched martial law order, and multiple charges.
His short-lived martial law declaration in December 2024 threw the country into months of turmoil.
A court is due to deliver its verdict in the insurrection trial of Yoon Suk Yeol.
Kim Keon Hee was also ordered to return a Graff diamond necklace and pay back 12.85m won in cash.
This is the first of the verdicts in the four trials linked to Yoon's shock decree in 2024.
Yoon is accused of leading an insurrection when he tried to impose martial law in 2024.
