At the
2012 Asian Championships, Lee won a bronze medal on the floor exercise behind
Kenzō Shirai and
Kim Han-sol. He represented
South Korea at the 2015 Summer Universiade and helped the
team win the silver medal behind Japan. Then at the
2015 Asian Championships, he won a bronze medal with the South Korean team and on the horizontal bar. He made his
World Championships debut in
2015 where South Korea placed seventh in the team final. Lee competed at the
2016 Glasgow World Cup and placed ninth in the all-around. He represented
South Korea at the 2018 Asian Games and helped the
team win the bronze medal behind China and Japan. He competed with the South Korean team that placed 13th in the qualification round of the
2018 World Championships. At the
2019 World Championships, Lee helped the South Korean team finish ninth in the qualification round, making them the first reserve for the team final. Additionally, this result earned South Korea a
team berth for the 2020 Olympics. After the World Championships, he competed at the
2019 Swiss Cup Zürich alongside
Yeo Seo-jeong, and they finished seventh. Lee finished second in the all-around at South Korea's Olympic Trials and was selected to represent
South Korea at the 2020 Summer Olympics alongside
Kim Han-sol,
Ryu Sung-hyun, and
Yang Hak-seon. At the Olympic Games, the team placed 11th during the
qualification round. Individually, he finished 22nd in the
all-around final. After the Olympic Games, he competed at the
World Championships but did not qualify for any finals. Lee finished fifth on the vault at the
2022 Doha World Cup. Then at the
2022 World Championships, he helped South Korea qualify for the team final and place eighth. Individually, he qualified for the vault final and placed sixth. At the
2023 World Championships, Lee finished 23rd in the all-around during the qualification round. With this result, he earned an
individual berth for the 2024 Olympic Games. He also finished 23rd in the all-around final. == Competitive history ==