| Challenger de Nouméa | 01/01 04:25 | 25 | [274] Yunseong Chung v Jurij Rodionov [217] | 4-6,1-6 | |
| Challenger de Nouméa | 12/31 00:30 | 24 | [262] Yunseong Chung v Tomislav Brkic [309] | 6-3,6-2 | |
| ITF Catar F5 | 12/11 12:00 | 25 | Yunseong Chung v Kristian Lozan | Cancelled | |
| Open de Australia - Comodín | 11/30 05:45 | 27 | Zhe Li v Yunseong Chung | 6-4,6-4 | |
| Open de Australia - Comodín | 11/29 03:50 | 26 | [402] Rigele Te v Yunseong Chung [266] | 6-7,1-6 | |
| Challenger de Kobe | 11/16 04:45 | 27 | [281] Yunseong Chung v Tatsuma Ito [163] | 2-6,3-6 | |
| Challenger de Kobe | 11/14 05:00 | 26 | [385] Nam Hoang Ly v Yunseong Chung [281] | 4-6,2-6 | |
| Challenger de Kobe | 11/13 02:00 | 25 | [281] Yunseong Chung v Jelle Sels [266] | 7-6,7-6 | |
| Challenger de Liuzhou | 10/23 03:35 | 25 | [149] Miomir Kecmanovic v Yunseong Chung [282] | Retired | |
| Challenger de Liuzhou | 10/22 04:45 | 54 | [282] Yunseong Chung v Emil Ruusuvuori [318] | 6-3,6-3 | |
| Challenger de Liuzhou | 10/21 07:00 | 46 | Yunseong Chung v Youssef Hossam | 7-5,6-3 | |
| Challenger de Liuzhou | 10/20 08:20 | 45 | Yunseong Chung v Sidharth Rawat | 5-7,6-2,6-3 | |
| Challenger de Ningbo | 10/19 03:00 | 27 | [291] Yunseong Chung v Prajnesh Gunneswaran [170] | 2-6,1-6 | |
| Challenger de Ningbo | 10/17 05:15 | 26 | [291] Yunseong Chung v Yosuke Watanuki [220] | 2-6,7-6,6-3 | |
| Challenger de Ningbo | 10/15 04:05 | 25 | [127] Ramkumar Ramanathan v Yunseong Chung [294] | 6-1,6-7,6-7 | |
| Challenger Taskent | 10/07 05:00 | 46 | Yunseong Chung v Artem Dubrivnyy | 3-6,5-7 | |
| Challenger Taskent | 10/06 05:00 | 45 | Yunseong Chung v Grigoriy Korobeynikov | 6-0,6-0 | |
| Challenger de Kaohsiung | 09/18 10:00 | 25 | [123] Jason Jung v Yunseong Chung [296] | 6-3,6-4 | |
| Challenger de Kaohsiung | 09/17 04:15 | 54 | [293] Yunseong Chung v Tristan Lamasine [345] | 6-4,6-2 | |
| Challenger de Kaohsiung | 09/16 07:45 | 46 | [293] Yunseong Chung v Xin Gao [276] | 7-5,6-3 | |
| Challenger de Kaohsiung | 09/15 12:10 | 45 | [293] Yunseong Chung v N. Vijay Sundar Prashanth [231] | 7-5,6-2 | |
| Challenger de Shanghái | 09/11 07:00 | 25 | [325] Aldin Setkic v Yunseong Chung [293] | 6-3,6-4 | |
| Challenger de Zhangjiagang | 09/07 03:00 | 27 | [315] Yunseong Chung v Alexander Bublik [203] | 4-6,4-6 | |
| Challenger de Zhangjiagang | 09/06 02:00 | 26 | [176] Go Soeda v Yunseong Chung [315] | 5-7,6-3,2-6 | |
| Challenger de Zhangjiagang | 09/05 02:00 | 25 | [315] Yunseong Chung v Roman Safiullin [292] | 3-6,6-4,6-3 | |
| Challenger Gwangju | 08/14 01:00 | 25 | [312] Yunseong Chung v Benjamin Lock [474] | 4-6,6-4,3-6 | |
| Challenger de Lexington | 08/04 19:50 | 28 | [338] Yunseong Chung v Stefano Napolitano [233] | 5-7,3-6 | |
| Challenger de Lexington | 08/03 23:00 | 27 | [338] Yunseong Chung v Jay Clarke [175] | Retired | |
| Challenger de Lexington | 08/02 14:00 | 26 | Jeffrey John Wolf v Yunseong Chung | 3-6,7-6,5-7 | |
| Challenger de Lexington | 08/01 01:15 | 25 | Yunseong Chung v William Bushamuka | 6-2,6-3 |
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.