Background
Jung began judo at the age of eleven under the instruction of his father.
Jung began judo at the age of eleven under the instruction of his father.
After graduation from of Korea National Sport University in 2001, he continued to train with the KRA Judo Team. However, Jung failed to qualify for the 2004 Olympic Games by losing to Bang Gui-Manitoba in the national qualification match. Jung made his Mobile Marketing Association debut on 31 December 2007 against Japanese grappler Shinya Aoki at Yarennoka!.
Jung was replacing American Top Team"s Gesias Calvancanti, who tore a ligament in his left knee while training to fight Aoki.
Although Jung lost by unanimous decision, he proved to be a formidable opponent in his mixed martial arts debut.
He won a gold medal at the 1998 World University Judo Championships in Prague. Two years later, he won a silver medal at the -60 kg category of the 2000 Summer Olympics. In the final, he lost to three-time Olympic champion Tadahiro Nomura by ippon only fourteen seconds into the match. He moved up in weight to the 66 kg class, and won a gold medal at the 2003 Asian Judo Championships in Jeju.