The novel depicts Gongsun Sheng as an eight chi tall Taoist priest with a noble look as his eyebrows slant apart like the Chinese character for "eight" (八) and his eyes are almond-shaped.
A native of Jizhou (薊州; present-day Ji County, Tianjin), he is a master of Taoist magic who could summon the wind and the rain, ride the mist and drive the clouds.
Gongsun Sheng learns that Liang Shijie, the prefect of Daming, is sending valuables to his father-in-law Grand Tutor Cai Jing in the capital Dongjing as birthday gifts.
Following Wu Yong's plan, the seven men, disguised as date traders, trick the escorts of the convoy led by Yang Zhi to down spiked wine at the Yellow Mud Ridge.
Forewarned by the county magistrate's clerk Song Jiang, Chao Gai, Wu Yong, Gongsun Sheng and Liu Tang flee to the home of the Ruan brothers in a fishing village.
The Liangshan outlaws get into a battle with Gaotangzhou (高唐州; around present-day Gaotang County, Shandong) in their attempt to rescue Chai Jin, who is jailed by the prefecture's governor Gao Lian.
Liangshan faces challenge from the outlaw band of Mount Mangdang (芒碭山; north of present-day Yongcheng, Henan) led by Fan Rui, Xiang Chong and Li Gun.
Gongsun Sheng is appointed as a top strategist of Liangshan alongside Wu Yong after the 108 Stars of Destiny have all come together in what is called the Grand Assembly.
After Liangshan put down the revolt of Wang Qing and before the campaign against Fang La commences, Gongsun requests to return to Jizhou to continue studying Taoism under Taoist Luo.