| Challenger - Gwangju | 04/18 02:00 | 26 | [171] Lloyd Harris v Yunseong Chung [383] | 6-4,6-4 | |
| Challenger - Gwangju | 04/16 03:15 | 25 | [383] Yunseong Chung v Paul Jubb [385] | 6-4,4-6,6-3 | |
| Challenger - Busan | 04/09 05:30 | 25 | [387] Yun-Seong Chung v Mark Lajal [211] | 3-6,2-6 | |
| Challenger - Busan | 04/08 02:30 | 19 | [331] Hiroki Moriya v Yun-Seong Chung [388] | 4-6,6-7 | |
| Challenger - Busan | 04/07 05:15 | 14 | [430] Stefanos Sakellaridis v Yun-Seong Chung [388] | 6-1,2-6,3-6 | |
| ITF - M15 Tsukuba | 03/29 06:45 | 27 | Yun-Seong Chung v Hikaru Shiraishi | 6-2,4-6,4-6 | |
| ITF - M15 Tsukuba | 03/28 01:30 | 26 | Yun-Seong Chung v Takuya Kumasaka | 7-6,1-6,6-4 | |
| ITF - M15 Tsukuba | 03/27 00:55 | 25 | Yun-Seong Chung v Yu Tanaka | 6-3,7-6 | |
| ITF - M15 Nishi-Tokyo | 03/23 01:00 | 26 | Takuya Kumasaka v Yunseong Chung | Cancelled | |
| ITF - M15 Nishi-Tokyo | 03/22 04:05 | 27 | Duckhee Lee v Yunseong Chung | 6-4,6-0 | |
| ITF - M15 Nishi-Tokyo | 03/21 00:55 | 26 | Linang Xiao v Yunseong Chung | 2-6,4-6 | |
| ITF - M15 Nishi-Tokyo | 03/20 02:30 | 25 | Masamichi Imamura v Yunseong Chung | 6-7,2-6 | |
| Challenger - New Delhi | 02/25 11:45 | 14 | Siddharth Vishwakarma v Yunseong Chung | Retired | |
| Challenger - Pune | 02/19 05:30 | 19 | Alexey Zakharov v Yunseong Chung | 6-3,5-7,6-4 | |
| Challenger - Pune | 02/18 08:15 | 14 | [379] Yunseong Chung v Rio Noguchi [334] | 7-5,7-6 | |
| Challenger - Bengaluru | 02/12 06:20 | 19 | [307] Chun Hsin Tseng v Yunseong Chung [381] | 7-5,4-6,6-2 | |
| Challenger - Bengaluru | 02/11 09:30 | 14 | Adil Kalyanpur v Yunseong Chung | 4-6,3-6 | |
| Challenger - Nonthaburi | 01/08 05:40 | 19 | Yunseong Chung v Christian Langmo | 2-6,0-6 | |
| Challenger - Nonthaburi | 01/07 07:20 | 14 | Yunseong Chung v Congsup Congcar | 7-5,6-1 | |
| Challenger - Nonthaburi | 12/31 06:25 | 14 | [372] Yunseong Chung v Kaichi Uchida [307] | 4-6,0-6 | |
| Challenger - Yokohama | 11/21 07:20 | 25 | [357] Yunseong Chung v Luca Nardi [118] | 2-6,4-6 | |
| Challenger - Yokohama | 11/20 03:35 | 19 | [301] Yasutaka Uchiyama v Yunseong Chung [362] | 6-4,6-7,7-6 | |
| Challenger - Yokohama | 11/19 05:25 | 14 | [429] Fajing Sun v Yunseong Chung [362] | 4-6,4-6 | |
| Challenger - Kobe | 11/16 02:00 | 26 | [362] Yunseong Chung v Jason Jung [242] | Retired | |
| Challenger - Kobe | 11/14 01:30 | 25 | Renta Tokuda v Yunseong Chung | 6-4,1-6,2-6 | |
| Challenger - Kobe | 11/13 01:30 | 19 | [400] Rio Noguchi v Yunseong Chung [362] | 1-6,4-6 | |
| Challenger - Kobe | 11/12 02:25 | 14 | Sanhui Shin v Yunseong Chung | 3-6,3-6 | |
| ATP - Newport | 07/18 22:05 | 25 | [322] Yunseong Chung v Steve Johnson [197] | 2-6,3-6 | |
| ATP - Newport | 07/17 19:45 | 19 | [242] Beibit Zhukayev v Yunseong Chung [322] | 4-6,3-6 | |
| ATP - Newport | 07/17 15:00 | 14 | Gage Brymer v Yunseong Chung | 3-6,6-7 |
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.