After Li Xian was removed as crown prince in 680 (after offending his mother, Emperor Gaozong's powerful empress Empress Wu (later known as Wu Zetian)), Wei was sent out of the capital to serve as the magistrate of Wucheng County (烏程, in modern Huzhou, Zhejiang), and it was said that he much improved the culture of the county.
During the Changshou era (692-694), by which time Empress Wu had established her own Zhou dynasty as its "emperor," interrupting Tang, Wei Chengqing served as Fengge Sheren (鳳閣舍人), a mid-level official at the legislative bureau of government (鳳閣, Fengge), and was further given the responsibility to select officials at the ministry of civil service affairs (天官部, Tianguan Bu).
He was eventually recalled to serve as deputy minister of civil service affairs (天官侍郎, Tianguan Shilang), and was also responsible for editing the imperial history.
After about a year, he was promoted to be the prefect of Chen Prefecture (辰州, roughly modern Huaihua, Hunan), but even before he reported to Chen Prefecture, was recalled to serve as honorary Mishu Shaojian (秘書少監, deputy head of the archival bureau, although in this case without actual authority) and again made an imperial historian.
Emperor Zhongzong had him draft a memorial text for Wu Zetian, and once he completed it, praised him for its beauty, giving him the honorific title Yinqing Guanglu Daifu (銀青光祿大夫).
He was soon commissioned to be Huangmen Shilang (黃門侍郎), the deputy head of the examination bureau (門下省, Menxia Sheng), but died of illness before he could take office.
Emperor Zhongzong mourned him greatly and recalled Wei Sili, then serving as a prefectural prefect, to succeed him.