While details on King's transfer were still scarce, the positive resolution of the King case was noteworthy given how rare diplomatic cooperation is between the United States, North Korea and China.
King, 23, made a sudden dash into North Korea from the South on July 18 while on a civilian tour of the Joint Security Area on the heavily fortified border between the neighbours and was immediately taken into North Korean custody.
His shocking case triggered heated discussions within the US government, but Washington declined to declare him a prisoner of war. Instead, North Korea appears to have treated his case like one of illegal immigration.
North Korea's KCNA state news agency said King had been expelled after admitting to entering North Korea illegally as he was "disillusioned about unequal US society."
North Korea's decision on the King matter, published by KCNA, detailed the final results of an investigation into King's July border crossing. Last month, it reported interim findings that he wanted refuge in North Korea or elsewhere because of maltreatment and racial discrimination within the US army.
"King confessed that he illegally intruded into the territory of the DPRK as he harbored ill feeling against inhuman maltreatment and racial discrimination within the US army and was disillusioned about the unequal US society," KCNA said.
DPRK refers to North's official name, the Democratic People's Republic of Korea. Authorities have decided to expel King under the country's law, KCNA said, but did not specify how, when or to where he would be expelled.
US officials told Reuters King was already in US custody after being expelled by North Korea into China, but did not offer further details ahead of an official US announcement.
The US State Department could not be immediately reached for comment. US Forces Korea and the United Nations Command did not immediately respond to requests for comment.
There have been several attempts by US soldiers stationed in South Korea to desert or defect to North Korea, but King's expulsion decision came relatively quickly. Others have spent years before being released from the reclusive country.
Jonathan Franks, spokesperson for King's mother, Claudine Gates, said: "Ms. Gates will be forever grateful to the United States Army and all its interagency partners for a job well done."
King's uncle, Myron Gates, told ABC News in August that his nephew, who is Black, was experiencing racism during his military deployment, and that after he spent time in a South Korean jail, he did not sound like himself.
King, who joined the US army in January 2021, faced two allegations of assault in South Korea. He pleaded guilty to one instance of assault and destroying public property for damaging a police car during a profanity-laced tirade against Koreans, according to court documents. He was due to face more disciplinary measures when he arrived back in the United States.
King had finished serving military detention and had been transported by the US military to the airport to return to his home unit in the United States. Instead, he left the airport and joined a tour of the border area, where he ran across despite attempts by South Korean and US guards to stop him.
Lim Eul-chul, a professor of North Korean studies at South Korea's Kyungnam University, said Pyongyang may have felt that any diplomatic and propaganda value in keeping King was outweighed by the likely US pressure it would face.
"It seems likely that North Korea saw little value in him as a countermeasure to a US human rights campaign against themselves by highlighting racial issues in America," he said.
Reporting by Hyonhee Shin in Seoul and Phil Stewart, Susan Heavey, Trevor Hunnicutt, Doina Chiacu, Humeyra Pamuk and David Brunnstrom in Washington and Brendan O'Brien in Chicago; Editing by Philippa Fletcher, Sharon Singleton and Bill Berkrot