He had at least one older brother, Shang Junzhang (尚君長), who, along with Wang Xianzhi, rose in rebellion against the Tang dynasty in 874 at Changyuan (長垣, in modern Xinxiang, Henan).
As of 876, Shang Rang was a major agrarian rebel commander, as it is known that that year, Yang Fuguang the eunuch monitor of the army Emperor Xizong sent against Wang Xianzhi, reported that Shang Rang had occupied Mount Chaya (查牙山, in modern Zhumadian, Henan), forcing the imperial forces sent against him to withdraw to Deng Prefecture (鄧州, in modern Nanyang, Henan).
However, Wang Xianzhi's ally Huang Chao angrily objected, causing the rebel army to turn against the peace agreement.
However, the Tang general Song Wei (宋威), who was against the negotiations, ambushed Shang Junzhang's party and took him and the other rebels on the way to Yang's camp captive.
He gave Shang the titles of Taiwei (太尉, one of the Three Excellencies) and Zhongshu Ling (中書令, i.e., head of the legislative bureau of government (中書省), one of the chancellors).
[3] Meanwhile, at Chang'an, an anonymous person wrote poems satirizing the Qi officials at the executive bureau (尚書省, Shangshu Sheng).
Shang, in anger, gouged out the eyes of the government workers who were on duty and hung them upside down, while arresting all in the city who were capable of writing poetry, putting some 3,000 of them to death.
In one of those battles in fall 881, Shang joined forces with Zhu Wen to repel the Tang generals Li Xiaochang (李孝昌) and Tuoba at the East Wei River Bridge, near Chang'an.
[3] However, when Shang attacked Yijun Camp (宜君寨, in modern Tongchuan, Shaanxi) in fall 882, he encountered a serious snowstorm, causing some 20-30% of his army to freeze to death.
[4] Huang Chao then changed target, deciding to attack Bian Prefecture (汴州, in modern Kaifeng, Henan), where Zhu Wen—who had by this point submitted to Tang and was serving as Tang's military governor of Xuanwu Circuit (宣武, headquartered at Bian Prefecture), and had changed his name to Zhu Quanzhong—was.
Li Keyong, hearing that Huang was attacking Bian Prefecture, quickly followed, and crushed the Qi forces as they were crossing the Yellow River north.
Shang surrendered to Shi Pu the military governor of Ganhua Circuit (感化, headquartered in modern Xuzhou, Jiangsu), one of the Tang generals participating in the campaign.