Pei Du
In 817, when the chancellor Pei Du left the capital Chang'an to oversee the campaign against the warlord Wu Yuanji, Cui was made "Zhongshu Shilang" (), the deputy head of the legislative bureau, as well as chancellor "de facto" with the title "Tong Zhongshu Menxia Pingzhangshi" (). Later that year, when Emperor Xianzong was set to make his close associate Zhang Su () a high-level consultant, Cui and fellow chancellor Wang Ya opposed, but Emperor Xianzong disagreed with them, only agreeing them when they, as a compromise, had Zhang made an "acting" consultant. Still, Zhang, as a result, resented the chancellors, and attacked them along with another close associate of Emperor Xianzong's, Huangfu Bo.