Jang Song-thaek was a mentor to the young North Korean dictator until he was publicly purged last week.
The once-powerful uncle of North Korean leader Kim Jong-un has been executed for treason after being branded "despicable human scum", according to the state news agency.
Jang Song-thaek was a mentor to the young North Korean dictator and one of the regime's most influential figures until he was publicly purged last week.
Pictures emerged of the 67-year-old Mr Jang being dragged out of his seat by police at a government meeting and official North Korean photographs were quickly doctored to remove all traces of him.
The Korean Central News Agency (KCNA) announced the execution of the man it described as "a traitor to the nation for all ages".
"Despicable human scum Jang, who was worse than a dog, perpetrated thrice-cursed acts of treachery in betrayal of such profound trust and warmest paternal love shown by the party and the leader for him," the agency said.
Mr Jang is the most high-profile figure to be cut down in what appears to be an ongoing purge by a resurgent military faction in Pyongyang. Two of his closest aides were executed earlier this week, according to the South Korean intelligence services.
Mr Jang was once considered a possible supreme leader of North Korea, who could hold power until the youthful Mr Kim came of age. Although he was passed over, he played a vital role in guiding the young leader's transition to power following the death of Kim Jong-il in December 2011.
He was rewarded with the post of vice-chairman of the powerful National Defence Commission, giving him major influence within both the party and the military.
His downfall is believed to have been orchestrated by rivals within the army but it is unclear whether Mr Kim supported his execution or had it forced upon him by senior military figures.
The KCNA report released on Friday morning accused him of being "an anti-party, counter-revolutionary" and nursing "a long-cherished greed for power".
In typically dramatic language, the official state organ said he attempted to "overthrow the state by all sorts of intrigues and despicable methods with a wild ambition to grab the supreme power of our party and state".
His purging has sent ripples of alarm through the region, where neighbouring countries have long feared that the hermit nation's regime could collapse into chaos.