| ITF M25 Aktobe | 02/19 07:15 | 25 | Riccardo Balzerani v Yunseong Chung | 6-3,4-6,4-6 | |
| ITF M25 Aktobe | 02/13 04:55 | 26 | Otto Virtanen v Yunseong Chung | 6-7,6-3,6-2 | |
| ITF M25 Aktobe | 02/12 10:40 | 25 | Yaraslav Shyla v Yunseong Chung | 6-7,6-7 | |
| ITF M25 Nonthaburi | 02/06 05:30 | 26 | [389] Matija Pecotic v Yunseong Chung [326] | 6-0,6-3 | |
| ITF M25 Nonthaburi | 02/05 09:45 | 25 | [439] Calvin Hemery v Yunseong Chung [326] | Retired | |
| Challenger de Bangkok | 01/12 06:40 | 24 | [335] Jack Draper v Yunseong Chung [320] | 7-6,6-3 | |
| Open de Australia - Comodín | 12/07 05:30 | 28 | [321] Yunseong Chung v Tatsuma Ito [148] | 6-1,4-6,4-6 | |
| Open de Australia - Comodín | 12/06 06:00 | 27 | [270] Sasikumar Mukund v Yunseong Chung [321] | 4-6,3-6 | |
| Open de Australia - Comodín | 12/04 04:00 | 26 | [321] Yunseong Chung v Denis Istomin [179] | 7-5,6-3 | |
| Challenger de Kobe | 11/05 05:35 | 25 | [297] Yunseong Chung v Yuichi Sugita [107] | 1-6,4-6 | |
| Challenger de Kobe | 11/04 04:00 | 24 | [297] Yunseong Chung v Yusuke Takahashi [452] | 7-6,7-6 | |
| Challenger de Shenzhen 2 | 10/29 02:00 | 24 | [296] Yunseong Chung v Jonas Forejtek [332] | 4-6,3-6 | |
| Challenger de Liuzhou | 10/23 02:00 | 25 | [297] Yunseong Chung v Alejandro Davidovich Fokina [93] | 5-7,5-7 | |
| Challenger de Liuzhou | 10/21 06:00 | 24 | [297] Yunseong Chung v Takuto Niki [481] | 6-2,7-6 | |
| Challenger de Ningbo | 10/16 03:35 | 25 | [281] Yunseong Chung v Danilo Petrovic [195] | 3-6,3-6 | |
| Challenger de Ningbo | 10/15 02:00 | 24 | Yunseong Chung v Aoran Wang | 1-6,6-2,6-1 | |
| Challenger de Kaohsiung | 09/17 01:30 | 24 | Yunseong Chung v Miliaan Niesten | 4-6,3-6 | |
| Challenger de Jinan | 09/02 02:00 | 24 | [263] Yunseong Chung v Kaichi Uchida [259] | 2-6,4-6 | |
| US Open | 08/20 16:20 | 44 | [102] Salvatore Caruso v Yunseong Chung [259] | 6-0,6-2 | |
| Challenger de Yokkaichi | 08/08 02:00 | 26 | [269] Yunseong Chung v Saketh Myneni [271] | 3-6,6-3,3-6 | |
| Challenger de Yokkaichi | 08/06 07:20 | 25 | Yunseong Chung v Alafia Ayeni | 7-6,6-3 | |
| Challenger de Chengdu | 07/31 04:55 | 25 | [237] Yunseong Chung v Dayne Kelly [475] | 3-6,6-4,2-6 | |
| Challenger de Nur-Sultan | 07/19 06:45 | 27 | [246] Yunseong Chung v Aleksandar Vukic [290] | 3-6,2-6 | |
| Challenger de Nur-Sultan | 07/18 05:00 | 26 | [246] Yunseong Chung v Goncalo Oliveira [260] | 6-7,7-5,6-4 | |
| Challenger de Nur-Sultan | 07/17 05:00 | 25 | [246] Yunseong Chung v Edan Leshem [398] | 6-4,4-6,6-4 | |
| Challenger de Nottingham | 06/11 18:40 | 24 | Jack Draper v Yunseong Chung | 5-7,6-0,6-2 | |
| Challenger de Surbiton | 06/05 13:15 | 25 | [249] Yunseong Chung v Peter Polansky [123] | 3-6,3-6 | |
| Challenger de Surbiton | 06/04 10:00 | 24 | Andrew Watson v Yunseong Chung | 2-6,2-6 | |
| Challenger Gwangju | 05/16 05:45 | 26 | [253] Yunseong Chung v Evgeny Donskoy [150] | 5-7,4-6 | |
| Challenger Gwangju | 05/15 03:40 | 25 | [241] Duckhee Lee v Yunseong Chung [253] | 4-6,2-6 |
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.