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