| ITF M25 - Kashiwa | 04/04 01:00 | 25 | Takeru Yuzuki v Yunseong Chung | 2-6,2-6 | |
| ITF M25 - Tsukuba | 03/29 00:30 | 25 | Kazuki Nishiwaki v Yunseong Chung | 6-2,6-3 | |
| Challenger - Pune | 02/28 13:00 | 25 | [241] Miljan Zekic v Yunseong Chung [358] | 6-3,6-4 | |
| Challenger - Pune | 02/27 07:05 | 19 | [299] Jay Clarke v Yunseong Chung [359] | 6-7,3-6 | |
| Challenger - Pune | 02/26 10:30 | 14 | Nitin Kumar Sinha v Yunseong Chung | 2-6,2-6 | |
| Challenger - Bengaluru | 02/20 07:25 | 19 | [320] Nikola Milojevic v Yunseong Chung [359] | 7-6,6-4 | |
| Challenger - Bengaluru | 02/19 11:15 | 14 | [424] Dayne Kelly v Yunseong Chung [360] | 6-7,4-6 | |
| Challenger - Manama | 02/12 08:00 | 14 | Yunseong Chung v Aleksandr Braynin | 5-7,4-6 | |
| Challenger - Concepcion | 01/22 15:30 | 14 | [128] Karol Drzewiecki v Yunseong Chung [335] | 6-3,6-2 | |
| Challenger - Piracicaba | 01/17 17:15 | 25 | [385] Carlos Sanchez Jover v Yunseong Chung [335] | 6-3,6-0 | |
| Challenger - Piracicaba | 01/16 15:10 | 19 | [335] Yunseong Chung v Carlos Sanchez Jover [385] | 6-4,6-3 | |
| Challenger - Piracicaba | 01/15 18:15 | 14 | Yunseong Chung v Gonzalo Bueno | 6-2,6-2 | |
| Challenger - Piracicaba | 01/15 17:00 | 14 | Yunseong Chung v Mateus D C C Alves | Cancelled | |
| Challenger - Tigre | 01/10 17:10 | 25 | [332] Yunseong Chung v Edoardo Lavagno [366] | 3-6,1-6 | |
| Challenger - Yokkaichi | 11/25 04:10 | 27 | [361] Yunseong Chung v Yosuke Watanuki [173] | Retired | |
| Challenger - Yokkaichi | 11/24 01:30 | 26 | [361] Yunseong Chung v Mukund Sasikumar [353] | 6-1,6-4 | |
| Challenger - Yokkaichi | 11/21 02:50 | 25 | [248] Dane Sweeny v Yunseong Chung [363] | 5-7,2-6 | |
| Challenger - Kobe | 11/15 02:50 | 25 | [363] Yunseong Chung v Yosuke Watanuki [196] | 2-6,2-6 | |
| Challenger - Kobe | 11/14 02:45 | 19 | [362] Yunseong Chung v Yuta Shimizu [404] | 6-2,7-6 | |
| Challenger - Kobe | 11/13 05:30 | 14 | Yunseong Chung v Duckhee Lee | 6-2,6-0 | |
| Challenger - Yokohama | 11/02 03:25 | 26 | [384] Yunseong Chung v Kaichi Uchida [172] | 6-7,3-6 | |
| Challenger - Yokohama | 11/01 02:55 | 25 | Masamichi Imamura v Yunseong Chung | 3-6,4-6 | |
| Challenger - Busan | 10/20 02:00 | 26 | [470] Seong Chan Hong v Yunseong Chung [395] | 6-3,7-5 | |
| Challenger - Busan | 10/18 06:35 | 25 | [395] Yunseong Chung v Chun Hsin Tseng [86] | 7-5,7-5 | |
| Challenger - Gwangju | 10/04 05:30 | 25 | [397] Yunseong Chung v Jisung Nam [222] | 6-1,3-6,5-7 | |
| Challenger - Gwangju | 10/03 04:00 | 19 | [397] Yunseong Chung v Seita Watanabe [401] | 6-2,7-6 | |
| ATP - Seoul | 09/27 10:00 | 25 | [121] Soonwoo Kwon v Yunseong Chung [426] | 7-6,6-7,6-1 | |
| ATP - Seoul | 09/25 03:50 | 19 | [412] Shintaro Mochizuki v Yunseong Chung [415] | 5-7,4-6 | |
| ATP - Seoul | 09/24 06:55 | 14 | [415] Yunseong Chung v Dalibor Svrcina [212] | 6-3,4-6,6-1 | |
| Challenger - Nonthaburi | 09/05 11:00 | 25 | [242] Yosuke Watanuki v Yunseong Chung [418] | Retired |
Chung Yun-seong (Korean: 정윤성; born 27 March 1998) is a South Korean tennis player.
Chung has a career high ATP singles ranking of No. 233 achieved on 22 July 2019. He also has a career high ATP doubles ranking of No. 129 achieved on 22 May 2023. Chung has won three doubles ATP Challenger titles as well as four ITF singles and five doubles titles.
On the junior tour, Chung had a career-high combined ranking of 3 achieved on 21 March 2016. Chung was a semifinalist at the 2016 Australian Open boys' singles event and the 2015 US Open boys' singles event where he fell to both eventual champions Oliver Anderson and Taylor Fritz, respectively. Chung was also a singles finalist at the Osaka Mayor's Cup in 2014.
He and Orlando Luz lost to Yishai Oliel of Israel and Patrik Rikl of the Czech Republic in the final of the 2016 French Open boys' doubles, 6–3, 6–4.