Samgeun was only thirteen years old when he took power after his father’s death. Since he was not fit to oversee the military, the armies continued to be overseen by General Hae Gu, who maintained actual political control.
In 478, Hae Gu made common cause with rebels led by Yeon Sin, based in Daedu Castle. Samgeun first sent the noble Jin Nam to capture the castle with 2,000 men, but he failed. He then sent Jin Ro, who defeated the rebels with 500 men, whereupon Yeon Sin fled to Goguryeo. With this event, the Jin clan gained great strength in Baekje.
The next year, Samgeun died, succeeded by Gonji's son.