Kim holds dual citizenship having been born in South Korea to a Korean mother and a Norwegian father.

He chose to compete for South Korea in 2015 to earn a ticket to the Pyeongchang 2018 Winter Olympic Games.

Having won the men’s classic sprint event at the 2017 Asian Winter Games in Japanese city Sapporo, he was a contender to claim a first medal in the discipline for South Korea in Pyeongchang but finished way down in 49^th place.

Kim also finished well out of contention in the 15 kilometres freestyle and 50km mass start classic competitions.

The 19-year-old reportedly took the decision to change allegiance after his disappointing performance.

He said he only wants to develop into "a better athlete" in the future.

"It was an inevitable decision on my part,"! Kim told Yonhap.

"I am terribly sorry to everyone who's been helping me along the way."

While competing for South Korea, Kim also won three medals, including two golds, at the 2016 Winter Youth Olympic Games in Lillehammer.

At Sapporo 2017, he also claimed the 10km classic silver medal and 4x7.5km relay bronze to add to his men’s classic sprint gold.

Prior to Kim, no Korean skier had won an Asian Winter Games gold in cross-country skiing. 

He said he would have been more confident in his future if he felt he was improving while competing for South Korea.

"I never felt that way and I didn't think it was worth putting my future at stake to ski here," Kim told Yonhap.

Norway topped the cross-country medal standings at Pyeongchang 2018 with seven golds, four silvers and three bronzes.

Three of the gold medals were either won solely by or with the help of Johannes Høsflot Klæbo, who Kim considers to be a source of inspiration. 

"I am two years younger and I think I'll have my chances," he told Yonhap. 

Kim said he still hopes to be able to help South Korean skiing and, according to The Chosun Ilbo, has pledged to invite promising cross-country skiers from the country to Norway for training.