He participated in the editing of a work known as the Essence of Pearls from the Three Religions (三教珠英, Sanjiao Zhuying) — a compilation of various poetry about Confucianism, Buddhism, and Taoism—a project headed by Wu Zetian's lovers Zhang Yizhi and Zhang Changzong and the imperial scholar Li Jiao.
After the work was complete, he was made Dianzhong Shi Yushi (殿中侍御史), a low level imperial censor.
Around this time, Cui Shi became Kaogong Yuanwai Lang (考功員外郎), a low level official at the ministry of civil service affairs.
The coup leaders were subsequently, after accusations by Wu Sansi, all exiled to the Lingnan region in 706 with provisions that they would never be allowed to return to the capital Chang'an.
However, Cui Shi warned Wu Sansi that if somehow they returned to the capital later, they would create problems for him, and that they should somehow be killed in exile.
Wu Sansi was killed in 707 in an unsuccessful coup by Emperor Zhongzong's crown prince Li Chongjun, and Cui Shi soon became closely associated with Emperor Zhongzong's powerful concubine Consort Shangguan Wan'er; traditional historians generally believed that they had an affair.
He and fellow chancellor Zheng Yin were also made acting deputy ministers of civil service affairs (吏部侍郎, Libu Shilang), making them in charge of selecting officials, and it was said that both he and Zheng violated civil service regulations, accepted bribes, and promoted inappropriate persons.
After intercession by Consort Shangguan, as well as Emperor Zhongzong's daughter Li Guo'er the Princess Anle and Li Guo'er's husband Wu Yanxiu (武延秀), Cui was instead made the prefect of Xiang Prefecture (襄州, roughly modern Xiangfan, Hubei), and Zheng was made the military advisor to the prefect of Jiang Prefecture.
However, later in the year, when Emperor Zhongzong was set to make sacrifices to heaven and earth south of Chang'an, he recalled both Cui and Zheng to attend to him during the ceremony, and Cui was soon made Shangshu Zuo Cheng (尚書左丞), one of the secretaries general of the executive bureau.
[a] In 710, Emperor Zhongzong died suddenly—a death that traditional historians believed to be a poisoning carried out by Empress Wei and Li Guo'er.
His son by a concubine, Li Chongmao the Prince of Wen, was poised to be named emperor, but before Li Chongmao officially took the throne, Empress Wei carried out a number of official movements in order to consolidate her power, and as part of these moves, Cui, who was then Libu Shilang, was again made chancellor with the designation Tong Zhongshu Menxia Pingzhangshi.
He was almost immediately recalled to serve again as deputy minister of civil service affairs and chancellor de facto, but later in the year was removed from that post and again became Shangshu Zuo Cheng.
He was soon made Taizi Zhanshi (太子詹事), the head of household for Li Longji, who had been created crown prince by that point.
He was further recognized for his role in building the new canal to Shang Prefecture, and was given the honorific title of Yinqing Guanglu Daifu (銀青光祿大夫).
Soon after Emperor Xuanzong's assumption of the throne, Cui Shi was made acting Zhongshu Ling (中書令), the head of the legislative bureau and a post considered one for a chancellor.
On July 29,[4] Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci.
Further, when Lady Yuan was interrogated, she stated that Cui Shi was the one who planned to poison Emperor Xuanzong.
The edict reached Cui at Jing Prefecture (荊州, roughly modern Jingzhou, Hubei), and he committed suicide there.