It is not known when Li Shizhi was born, but it is known that his grandfather was Li Chengqian, the oldest son of the original crown prince of Tang Dynasty's second emperor . Li Chengqian was deposed in 643 but spared, and his line was bypassed in the subsequent succession, which eventually went to his brother . Li Shizhi's father Li Xiang served as a prefectural secretary general during the reign of Emperor Gaozong's wife Wu Zetian, but was removed by her. Li Shizhi himself started his public service as an officer of the imperial guards during the second reign of Emperor Gaozong's son .
During Emperor Xuanzong's reign
In the middle of the ''Kaiyuan'' era of Emperor Zhongzong's nephew , Li Shizhi became the prefect of Tong Prefecture . He was known for being able, and after the imperial attendant Han Chaozong surveyed the region, Han recommended him to Emperor Xuanzong. He thereafter successively served as the commandant at Qin Prefecture , the prefect of Shan Prefecture , 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 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 Daifu'' , 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. Emperor Xuanzong agreed, and further posthumously created Li Chengqian a prince and Li Xiang a duke, as well as bestowing posthumous honors on Li Shizhi's uncle Li Jue and several of Li Shizhi's brothers. They were buried together in a grand ceremony. Li Shizhi was soon made the minister of justice . It was said that Li Shizhi liked entertaining guests, and that he was able to drink two liters of wine without being drunk. Although he spent nights entertaining guests and only days on the affairs of state, he was able to get everything done.
In 739, Li Shizhi became the secretary general at You Prefecture and acting military governor of the region.
In 742, after the death of the Niu Xianke, Li Shizhi succeeded Niu as ''Zuo Xiang'' -- the head of the examination bureau of government and a post considered one for a chancellor; he was also created the Duke of Qinghe. He served alongside Li Linfu, and they fought over control of government, although since Li Shizhi was not a deep thinker, Li Linfu was able to find ways to damage him. For example, on one occasion, Li Linfu told Li Shizhi that there were gold deposits at Mount Hua that could be mined -- and Li Shizhi, as Li Linfu intended, then proposed to Emperor Xuanzong to mine the gold deposits. Li Linfu then pointed out that pursuant to Taoist principles, he believed that a mine at Mount Hua would damage Emperor Xuanzong's health, thus bringing imperial displeasure on Li Shizhi. In another incident, in 745, with Li Shizhi also serving as the minister of defense and Emperor Xuanzong's son-in-law Zhang Ji serving as deputy minister and whom Li Linfu also disliked, Li Linfu had some 60 officials at the minister of defense accused of corruption, and then coerced confessions out of them by torture, intending to use this to discredit Li Shizhi and Zhang, although neither was punished. However, subsequently, Li Linfu was able to accuse several officials friendly with Li Linfu -- Huangfu Weiming , Wei Jian , Pei Kuan , and Han Chaozong -- and get them demoted or exiled. Li Shizhi, in fear, offered to resign the chancellor position, and in 746 was removed from his chancellor post, becoming an advisor to the new crown prince . He wrote a poem in which he lamented that after he was removed, not even his family and friends were visiting him.
Later in 746, however, when Li Linfu made further accusations against Wei, Li Linfu implicated a large number of Wei's associates, including Li Shizhi. Li Shizhi was thus demoted to be the governor of Commandery. In 747, when Li Linfu was able to get Emperor Xuanzong to send the imperial censor Luo Xishi to various commanderies to execute Wei and several other officials implicated, the commanderies were terrorized. As Luo was approaching Yichun, Li Shizhi was fearful and committed suicide.