While his maternal half-elder brothers, FUJIWARA no Nagate and Matate were in confrontation with FUJIWARA no Nakamaro, it was presumed that Mitate was a close aide to Nakamaro regarding his promotion and relationship with his relatives.
同母兄の藤原永手や眞楯が藤原仲麻呂と対立したのに対し、御楯はその出世内容や親族関係から仲麻呂の側近であったと推測されている。