In November 2020, the year he turned 17, he won the 100 m freestyle at the national team trials in Gimcheon, North Gyeongsang, in a national record of 48.25. The next day he set a world junior record of 1:45.92 in the 200 m freestyle.
The breakthrough yearIn May 2021, the year he turned 18, he rewrote the national records again at the national team trials, with 48.04 in the 100 m freestyle and 1:44.96 in the 200 m, and he was named joint flag bearer of the Korean team with Kim Yeon-koung for the Tokyo Olympics opening ceremony. In the Olympic 200 m freestyle heats he broke Park Tae-hwan’s national record and then placed seventh in the final. In the 100 m freestyle semifinals he set an Asian record and became the first Asian swimmer in 65 years to reach the Olympic final in the event, and in the final he placed fifth, the best result by an Asian swimmer in 69 years. After five golds and the MVP award at the National Sports Festival, he won the 200 m freestyle at the Short Course World Championships in December, his first gold at a major event.
In 2022, he won silver in the 200 m freestyle at the World Championships in Budapest, Hungary, and four golds at the National Sports Festival. In December, he won the 200 m freestyle at the Short Course World Championships in Melbourne, Australia, in an Asian record for a second straight title.
In July 2023, he won bronze in the 200 m freestyle at the World Championships in Fukuoka, Japan. In August, while driving to the Jincheon training center, he hit and injured a pedestrian crossing at a crosswalk. At the Hangzhou Asian Games in September he won gold in the 200 m freestyle and the 800 m freestyle relay, silver in the 400 m medley relay and 400 m freestyle relay, and bronze in the 100 m freestyle and the mixed medley relay. At the National Sports Festival he won five golds and was named MVP for a third straight year.
In February 2024, the year he turned 21, a 1 million won fine over the 2023 Jincheon accident was finalized. At the World Championships in Doha, Qatar, he became the first Korean to win gold in the 200 m freestyle, and he reached his first final in the 100 m freestyle, placing fifth. In the 800 m freestyle relay he added silver, Korean swimming’s first team medal at the World Championships.
At the Paris Olympics in July, he was eliminated in the 200 m freestyle semifinals and withdrew from the 100 m semifinals to focus on the relay. In the 800 m freestyle relay he placed sixth, Korean swimming’s best result in an Olympic team event. He won five golds at the National Sports Festival for a second straight year and began basic military training as arts and sports personnel in November.
In July 2025, the year he turned 22, he placed fourth in the 200 m freestyle at the World Championships in Singapore, ending his medal streak at three straight championships. The 800 m freestyle relay finished fifth, and the 400 m medley relay placed seventh in the first final Korea had reached. In October, he swam 1:43.92 in the 200 m freestyle at the National Sports Festival, breaking Sun Yang’s Asian record, and also set national records in the individual medley and the relay to take his fourth career MVP award.
In September 2026, the year he turned 23, he won bronze in both the 100 m freestyle and the 800 m freestyle relay at the Aichi-Nagoya Asian Games.
Hwang Sun-woo (born May 21, 2003) debuted on Nov 18, 2020, the year he turned 17, when he set a national record in the 100 m freestyle at the national team trials, and became known on Jul 29, 2021, the year he turned 18, when he became the first Asian swimmer in 65 years to reach the Olympic 100 m freestyle final at the Tokyo Olympics. He won his first World Championships gold in 2024, the year he turned 21.
Ages are by calendar year (the year minus the birth year), birthdays aside.