Starting his career in 2015, Jung compiled a 11–2 record fighting for various East Asian regional promotions, with his most memorable accomplishment being winning the HEAT Light Heavyweight Championship via TKO against Yuto Nakajima.
[8] Da Un Jung was scheduled to face Ed Herman on May 2, 2020, at UFC Fight Night: Hermansson vs.
[9] However, on April 9, Dana White, the president of UFC announced that the event was postponed to a future date.
[11] However, Jung was removed from the bout on July 23 due to alleged travel restrictions related to the COVID-19 pandemic.
[16] As the first bout of his new contract, Jung was scheduled to face Shamil Gamzatov on April 10, 2021, at UFC on ABC 2.
[17][18] However, Gamzatov was removed from the bout on March 24 due to alleged Visa issues and replaced by William Knight.