Guo Jing's hometown is in Niu Family Village. His father, Guo Xiaotian, was from Shandong but moved to Lin'an (present-day Hangzhou) after the Jurchen-led Jin Empire conquered the northern part of the Song Empire in the Jin–Song Wars. Guo Xiaotian met Li Ping in Lin'an and married her. Two years after their marriage, Guo Xiaotian was killed by a group of soldiers led by Duan Tiande during a raid ordered by Wanyan Honglie. Li Ping, who was pregnant with Guo Jing then, was captured and held hostage by Duan Tiande, but managed to escape later. She fled north and arrived in Mongolia, where she gave birth to Guo Jing. Guo Jing and his mother are taken in by some nomads later and become part of Genghis Khan's tribe. Guo Jing befriends the Khan's children and followers, and becomes "anda" (sworn brothers) with the Khan's fourth son, Tolui. He later meets the "Seven Freaks of Jiangnan" and learns martial arts from them. During battles between the Khan and his rivals, Guo Jing demonstrates his loyalty to the Khan by helping to fend off the attackers. The Khan sees Guo Jing as a loyal subject, places great faith and trust in him, and betroths his daughter, Huazheng, to him.