Zheng was from Suzhou, Zhexi. He was born with a pale complexion and had long beard, a lean body, and broad shoulders. Due to his fair complexion and handsome good looks, he was nicknamed 'Fair-skinned gentleman' (白面郎君).
Zheng was an expert in martial arts, having learnt since young. He travelled around the country, making friends with other extraordinary people. Once, Zheng passed by Qingfeng Mountain and had a fight with Wang Ying, in which neither emerged the victor. In the end, Yan Shun was impressed with Zheng's skills and invited Zheng to join his band, which Zheng agreed.