Sung scored a 4-2 win over Singapore`s Lien TEC in a five-minute contest.
The South Korean jujitsu athlete, who was on the red corner, waged a fierce competition with Lien before taking the lead to claim a victory.
With the defeat, Lien, who edged out Indonesia`s Julia Simone, won the silver medal.
The bronze medal went to Jordan`s Kakish Yara, after she defeated Turkmenistan`s Krovyakova Violetta.
Reporting by Taufik Ridwan
Editing by Suharto