He was born to Gongsun Kang, Governor of Liaodong, Xuantu, Lelang and Daifangcommanderies. After Kang's death, his brother Gong took over the position in 221, but revealed his inability to rule. In 228, Yuan wrested the position.
At that time, China was split into Three Kingdoms. The Kingdom of Wei in the north and Kingdom of Wu in the south made efforts in bringing over the powerful warlord, but his indecisiveness eventually annihilated himself. Although Gongsun Yuan was nominally subject to Wei, Sun Quan, King of Wu, aggressively worked on him. Yuan considered switching sides to Wu until he yield under the pressure of Emperor Ming of Wei. Yuan killed Wu delegates, but some of them fled to Goguryeo, who was suffred from constant pressure from the Gongsun family. Then Wu allied with Goguryeo to launch a pincer attack against Yuan. However, Goguryeo was nervous about the risk and killed Wu delegates.
Feeling a sense of crisis, Emperor Ming decided to overthrow the Gongsun family. In 237, he dispatched Wuqiu Jian with Chinese, Wuhuan and Xianbei troops, but the campaign was aborted due to floods. Gongsun Yuan proclaimed himself as the King of Yan (燕) and concluded an alliance with Wu. In the next year, Sima Yi and Wuqui Jian attacked Liaodong again. As a result of the campaign, Gongsun Yuan was killed and the Gongsun family was exterminated. The Kingdom of Wei conquered Liaodong and northwestern Korea.
Gongsun Zan then feared that Yuan Shu would find out about his objections and bear a grudge against him, so he changed tack and sent his cousin Gongsun Yue (in the novel, Yue is a younger brother) with 1,000 cavalry to aid Yuan Shu.
Gongsun Zan led his troops to the Pan River and wrote a memorial to the imperial court (then in Chang'an), accusing Yuan Shao of numerous crimes.
Gongsun lived in the tower with his concubines, and no one was allowed to enter - all messages to him had to be tied to a rope which would be pulled up by a concubine.
Gongsun Kang (公孫康 gong1 sun1 kang1; ?-221) was a Chinese warlord in Liaodong[?] and northwestern Korea.
He was born to Gongsun Du[?], the Governer of Liaodong.
In 207 he pleased Cao Cao in killing Yuan Shang[?] (袁尚), the last attested member of the clans of Yuan Shao[?] and escaped the conquest of Cao Cao to Liaodong.