What is known is that he was an army officer from Taining Circuit (泰寧, headquartered in modern Jining, Shandong) who participated in the operations against the major agrarian rebel Huang Chao early in the reign of Emperor Xizong.
[3] Meanwhile, with Liu Jurong having returned to Shannan East after defeating Huang, and with the overall commander of the operations, the former chancellor Wang Duo, who was also the military governor of Jingnan, having fled prior to Cao's and Liu's defeat of Huang Chao, there was no military governor around to govern Jingnan Circuit.
The eunuch monitor of the army in the region, Yang Fuguang, put Song Hao (宋浩), an officer from Zhongwu Circuit (忠武, headquartered in modern Xuchang, Henan) in charge of the circuit until the imperial government could commission a replacement.
[2] Duan Yanmo and the new eunuch monitor, Zhu Jingmei, soon developed an adversarial relationship.
Zhu initially made the deputy mayor of Jiangling, Li Sui (李燧), acting military governor, and then, when Emperor Xizong commissioned Zheng again but Zheng hesitated to report to Jingnan, put the officer Chen Ru in charge.