Seo Seung-jae (; born 4 September 1997) is a South Korean badminton player. A three-time World champion, he is the first South Korean player in 24 years to have won two gold medals in a single edition of the BWF World Championships, by winning the mixed and men's doubles event at the 2023 BWF World Championships, partnering with Chae Yoo-jung and Kang Min-hyuk respectively. He competed at the 2017 Sudirman Cup and helped the Korean national team to its fourth trophy. He then went on to win his second men's doubles title in the 2025 BWF World Championships with his partner Kim Won-ho.
In 2014, Seo competed at the Summer Youth Olympics in Nanjing, China.
As a student of Wonkwang University, Seo was entrusted to take part in the 2017 Summer Universiade in Taiwan. He managed to win the men's doubles gold medal with Kim Jae-hwan.
Seo competed at the 2020 Summer Olympics in the men's doubles partnered with Choi Sol-gyu and in the mixed doubles with Chae Yoo-jung. He was eliminated in the group stage and quarter-finals respectively. After the Olympics, Seo played at the Sudirman Cup and the Thomas Cup, where Korea did not get any medal in both events. He only played two BWF World Tour tournaments in 2021, the Indonesia Masters and Indonesia Open.
In 2022, Seo officially started a new partnership with his junior Kang Min-hyuk. The duo immediately caught attention by winning the Korea Open, defeating higher-ranked pairs such as Satwiksairaj Rankireddy and Chirag Shetty, Mohammad Ahsan and Hendra Setiawan, and their final opponent Fajar Alfian and Muhammad Rian Ardianto in the journey. The duo also won all their matches in the Thomas Cup. However, Seo and Kang saw their results fluctuate throughout 2022, with notable early exits at the Japan Open, Malaysia Open, and the French Open. Seo resumed playing mixed doubles with Chae Yoo-jung at the Indonesia Masters as semi-finalists. The Seo and Chae combination became champions at the Australian Open over teammates Jeong Na-eun and Kim Won-ho, as well as semi-finalists at the Indonesia Open and quarter-finalists at the World Championships.
2023 was Seo's breakthrough year. He won the World Championships in both mixed doubles and men's doubles with his first victory over the world number 1 Zheng Siwei and Huang Yaqiong in mixed doubles, as well as overcoming home favorites Kim Astrup and Anders Skaarup Rasmussen in men's doubles. He also secured his first ever Super 1000 title at the China Open with a second consecutive victory over Zheng and Huang at the quarter-finals. Thanks to his achievements, Seo was awarded the Male Player of the Year for 2023. He completed the year with his first ever World Tour Finals title, this time from men's doubles, after winning against reigning world number 1 Liang Weikeng and Wang Chang.
Started the 2025 season with new partner, Seo and Kim Won-ho emerged victorious at the opening tournament of the BWF World Tour in the Malaysia Open. Seo continuing his good form in the next tournament by being a runner-up in India Open and winning Thailand Masters with another partner, Jin Yong. In March, Seo paired with Kim again and won German Open against France's Popov brothers (Toma Junior and Christo) as well as the All England against Leo Rolly Carnando and former winner Bagas Maulana.
Seo's partnership with Kim Won-ho failed to perform up to expectations when they shockingly crashed out in the 2nd round of the 2025 Asia Championships in April.
However, they bounced back quickly, reaching the final in the Singapore Badminton Open and eventually losing to the Malaysian pairing of Aaron Chia and Soh Wooi Yik, before winning the Indonesia Open a week later.
Men's doubles
Mixed doubles
Mixed doubles
Mixed doubles
Men's doubles
Boys' doubles
Boys' singles
The BWF World Tour, which was announced on 19 March 2017 and implemented in 2018, is a series of elite badminton tournaments sanctioned by the Badminton World Federation (BWF). The BWF World Tour is divided into levels of World Tour Finals, Super 1000, Super 750, Super 500, Super 300, and the BWF Tour Super 100.
Men's doubles
Mixed doubles
The BWF Grand Prix had two levels, the Grand Prix and Grand Prix Gold. It was a series of badminton tournaments sanctioned by the Badminton World Federation (BWF) and played between 2007 and 2017.
Men's doubles
Mixed doubles
Men's doubles