He was eventually made Zhuzuo Lang (著作郎), a low level official at the Palace Library, and was involved in editing imperial histories.
During the Chang'an era of Emperor Taizong's daughter-in-law Wu Zetian (701–705), Wei Zhigu successively served as Fengge Sheren (鳳閣舍人)—a mid-level official at the legislative bureau of government (鳳閣, Fengge)—and deputy minister of military supplies (衛尉少卿, Weiwei Shaoqing).
Soon thereafter, Wei Zhigu was made deputy minister of civil service affairs (吏部尚書, Libu Shangshu) and was again responsible for editing imperial histories.
In 711, he was made You Sanqi Changshi (右散騎常侍), a senior advisor at the legislative bureau (then named Zhongshu Sheng (中書省)).
Emperor Ruizong did not accept them, but thanked him for his honesty and gave him the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor de facto.
Soon thereafter, Wei Zhigu was made Shizhong (侍中), the head of the examination bureau and a post considered one for a chancellor.
On July 29,[1] Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci.
In winter 713, Wei went to the eastern capital Luoyang to carry out a selection process for officials there, and was considered to have done an exceptional job, drawing praises from Emperor Xuanzong.
By this point, Yao Chong, who had previously served as Wei's superior during Wu Zetian's reign, was again chancellor and was well-trusted by Emperor Xuanzong.