| K League 1 2021 Relegation - Appearances as Assistant | ||||
| 03/11/2021 | Seongnam FC | - | Incheon United | 1:1 |
| 28/11/2021 | FC Seoul | - | Gangwon FC | 0:0 |
| K League 1 2021 Relegation - Appearances as Assistant | ||||
| 03/11/2021 | Seongnam FC | - | Incheon United | 1:1 |
| 28/11/2021 | FC Seoul | - | Gangwon FC | 0:0 |
| Complete name: | Joo-kyung Sung |
| Born: | |
| Place of birth: |
South Korea |
| Nationality: |
South Korea |