He was known for writing poems filled with puns (xiehouyu) that satirized the political scene that impressed Emperor Zhaozong, leading to his brief term as chancellor despite his own misgivings.
)[2] When the imperial official Wang Hui served as the chief imperial censor,[5] he recommended Zheng to serve as Bingbu Langzhong (兵部郎中), a supervisory official at the ministry of defense (兵部, Bingbu), and also oversee the administration of the office of the censors (御史臺, Yushi Tai).
When Emperor Xizong was set to commission Du Honghui (杜弘徽), the younger brother of the chancellor Du Rangneng, as a Zhongshu Sheren (中書舍人, mid-level official at the legislative bureau (中書省, Zhongshu Sheng)), Zheng, in his duty of reviewing edicts, sealed and returned the edict to the emperor, arguing that it was inappropriate for one brother to oversee another (the chancellors had overall supervisory authority over the legislative bureau).
[2] Soon thereafter, Zheng was recalled to the imperial government to serve as Zuo Sanqi Changshi (左散騎常侍), a high-level advisory official at the examination bureau (門下省, Menxia Sheng).
The ruling officials disliked this phenomenon and made him the principal of the imperial university (國子祭酒, Guozi Jijiu).
[2] In 894, he issued an edict making Zheng the deputy minister of rites (禮部侍郎, Libu Shilang) and a chancellor with the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事).
He submitted several petitions declining the commission, but the emperor took no heed of them, so he felt compelled to report to his post as a chancellor.