He hailed from Gaoyang 高陽 (modern Gaoyang, Hebei) and lived a life as a shepherd in his youth. Yet his love for learning helped him obtaining the post of a local jail overseer and later that of steward (jishi 給事) of the local governor (taishou 太守). Besides managing the paperwork of the governor he studied the Confucian Classics Shangshu 尚書 and Lunyu 論語 and was soon promoted as a clerk in the staff of the regional inspector (cishi 刺史) of Youzhou 幽州.
For some time he acted on behalf of the salt manager (yanguan 鹽官) of Liaoxi 遼西. At the beginning of Emperor Yuan's 漢元帝 (r. 49-33 BCE) reign he was magistrate (ling 令) of Huaili 槐里. Because of his excellent performance he was promoted to governor of Anding 安定. He fought against corruption and the injustice of the rich landowners but was soon charged of cruelty and dismissed.
Yet not soon after he was made commandant (xiaowei 校尉) under the general pacifying the Qiang barbarians (huo Qiang jiangjun 護羌將軍) and was entrusted with the transport of grain in the logistics. He displayed greatest bravery in the defense of the supply lines without being rewarded. Wang Zun was, on the contrary, put into jail for leaving his position.
A third time he could start his career after recommendation of Xu Ming 徐明 and was appointed magistrate of Mei 郿, and soon promoted to regional inspector of Yizhou 益州, then counsellor (xiang 相) to the Prince of Dongping 東平. Upon the recommendation of General-in-chief (da jiangjun 大將軍) Wang Feng 王風 he was made metropolitan commandant (sili xiaowei 司隸校尉) but was then demoted to magistrate of Gaoling 高陵 because of his differences with the Counsellor-in-chief (chengxiang 丞相) Kuang Heng 匡衡.
Wang Feng again supported him so that Wang Zun became Grand master of remonstrance (jian dafu 諫大夫) and then Defender of the capital (jingfu duwei 京輔都尉). In 29 BCE he was appointed metropolitan magistrate (jingzhao yin 京兆尹), yet again dismissed because of cruelty. At that time the inhabitants of the capital remonstranted against this unjust charge so that Emperor Cheng 漢成帝 (r. 33-7 BCE) was moved by the people, pardoned him and appointed Wang Zun regional inspector of Xuzhou 徐州, later governor of Dongjun 東郡.
In this position he displayed the utmost spirit of benevolence and cooperation with the people when the dykes of the Yellow River broke. Wang Zhang died in office.