At the death bed of Empress Genmei, Fusasaki was appointed to Uchitsuomi (an important governmental post presiding over state affairs while assisting the Emperor), which was the post occupied by his grandfather FUJIWARA no Kamatari, as a guardian of Emperor Shomu, who was the Crown Prince at that time, as the Empress credited his talent.
元明天皇が死の床で祖父・藤原鎌足以来の内臣に任じて、皇太子聖武天皇の後見役を託したのもその才能を見越しての事であった。