Thereafter, he showed prudence and caution in how he responded to the Imperial decree to hunt down and destroy MINAMOTO no Yoritomo requested by MINAMOTO no Yoshitsune and issued by the Cloistered Emperor Goshirakawa, so that even after Yoshitsune fled the capital, upon Yoritomo's recommendation he was pressed into service as one member of his ten-man council of nobles; in the tenth month of 1186 he was made Udaijin (Minister of the Right), and then in the seventh month of 1189 he ascended to Sadaijin (Minister of the Left), thereafter becoming popularly known as "Tokudaiji Sadaijin," and working as Kanezane KUJO's right-hand man to facilitate relations between the court and the shogunate.
その後の源義経と後白河法皇による源頼朝追討院宣には慎重な姿勢を示したので、義経亡命後、源頼朝の推挙で議奏公卿十人の一人に押され、文治2年（1186年）10月には右大臣、文治5年（1189年）7月に左大臣となり、世に後徳大寺左大臣と称されて、九条兼実の片腕として朝幕関係の取り次ぎに活躍した。