He was made emperor in c.March 554 after his older half-brother Yuan Qin was deposed by the paramount general Yuwen Tai.
However, nothing else is known about his activities during his father's reign, during which the paramount general Yuwen Tai largely controlled power.
During Yuan Kuo's stint as the Prince of Qi, he married the daughter of the general Ruogan Hui (若干惠) as his wife and princess.
Emperor Gong appeared to be even more powerless than his father and brother, and the power remained in Yuwen's hands.
In fall 556, while Yuwen Tai was on a tour of the northern provinces, he became ill at Qiantun Mountain (牽屯山, in modern Guyuan, Ningxia).
Emperor Gong was subsequently forced to create Yuwen Jue the greater title of Duke of Zhou.