Lee made his first international appearance at the 2018 Junior World Championships in Tomaszów Mazowiecki . There he won the silver medal in the all-around competition. He ran his first World Cup races in Calgary at the beginning of the 2018/19 season . There he took 16th place over 500 m, third place in the mixed relay and second place over 1500 m and with the relay. In the further course of the season he was second in Salt Lake City over 1500 m and in Almaty third over 1000 m and 1500 m and second with the mixed relay. At the end of the season, he reached 17th place in the World Cup over 1000 m and third place in the World Cup over 1500 m. At the season highlight, the 2019 World Championships in Sofia , he won the bronze medal in the 1500 m and the gold medal with the relay. At the beginning of the following season he was in Montreal third with the mixed relay and over 1500 m and second with the relay. In the further course of the season he won in Shanghai over 1500 m, in Dresden with the relay and in Dordrecht over 500 m. He also took third place once and second place five times, making it fourth in the 500 m World Cup and second in the 1500 m World Cup. At the Four Continents Championships in Montreal in 2020 , he won the gold medal with the relay.
South Korea
Shanghai
Dordrecht
Dresden 1