He thereafter successively served as the commandant at Qin Prefecture (秦州, roughly modern Tianshui, Gansu), the prefect of Shan Prefecture (陝州, roughly modern Sanmenxia, Henan), and then mayor of Henan Municipality, to which the eastern capital Luoyang belonged.
It was said that Li Shizhi's governance was simple and straightforward, and that he did not dwell on details, to the relief of the officials and people under him.
While at Luoyang, he was responsible for building three major levees that alleviated flooding problems that plagued Luoyang, and when a monument was subsequently erected to commemorate his contributions, Emperor Xuanzong had his son Li Lin (李璘) the Prince of Yong write the text and Li Ying the Crown Prince write the heading, a great honor for Li Shizhi.
Li Shizhi later served as Yushi Dafu (御史大夫), the chief imperial censor.
In 736, Li Shizhi, lamenting the fact that neither his grandfather nor his father, on account of their removals, received an honored burial, requested that they be allowed to be reburied near the tomb of Emperor Taizong.
In 742, after the death of the chancellor Niu Xianke, Li Shizhi succeeded Niu as Zuo Xiang (左相) -- the head of the examination bureau of government (門下省, Menxia Sheng) and a post considered one for a chancellor; he was also created the Duke of Qinghe.