Hwang had his first international success in January 2016 at the Short Track Junior World Championships in Sofia . There he won the silver medal with the relay. The following month he won the gold medal in the 1000 m at the 2016 Winter Youth Olympic Games in Lillehammer . He made his debut in the Short Track World Cup at the beginning of the 2016/17 season in Calgary , which he finished in eighth place over 500 m. At the following World Cup station in Salt Lake City , he achieved his first podium finish in the World Cup with second place over 1000 m. In the further course of the season he achieved second place over 500 m and 1000 m and third place in the relay in Dresden and won his first World Cup victory in Minsk over 1000 m. He finished the season in eighth place in the World Cup over 500 m and fourth in the World Cup over 1000 m. At the beginning of the following season he took third place over 500 m and second place over 1000 m and 1500 m in Budapest . In Dordrecht he won the 1500 m and also came third in the 500 m. At the following World Cup in Shanghai he triumphed over 1500 m and took second place over 1000 m and 1500 m in Seoul . He achieved fourth place in the World Cup over 500 m, second place in the World Cup over 1000 m and first place in the World Cup over 1500 m. At the 2018 Winter Olympics in Pyeongchang , he won the silver medal over 500 m and took fourth place in the relay. In March 2018 he won the bronze medal in the all- around competition and the gold medal over 500 m and with the relay at the World Championships in Montreal .
In the 2018/19 season, Hwang won over 1000 m in Dresden and over 500 m and 1000 m in Turin . In addition, he finished second in the 500 m in Dresden and third in the 1500 m in Almaty and at the end of the season he finished fifth in the 1000 m World Cup and fourth in the 500 m World Cup. At the 2019 World Championships in Sofia , he won the silver medal in the all-around event and over 1000 m and the gold medal over 500 m and relay. At the beginning of the following season he triumphed in Salt Lake City over 500 m and 1000 m and in Montreal over 1000 m. In addition, he won second place there with the relay and second place in Montreal over 500 m. He finished seventh in the world cup over 500 m and fourth place in the world cup over 1000 m. At the Four Continents Championships in Montreal in 2020 , he won gold in the 500 m, 1000 m, 1500 m, with the relay and in the all-around competition.