After his uncle, Tomomasa HIRAGA was implicated in the Makishi Incident and executed in 1205, he succeeded to Shugo (a provincial military governor) of Iga and Isa provinces and took charge of maintaining security of Heian-kyo (the ancient capital of Japan in current Kyoto) as a Gokenin in Kyoto.
元久2年（1205年）に叔父の平賀朝雅が牧氏事件に連座して誅された後、朝雅の有していた伊賀国・伊勢国の守護を継承し、在京御家人として平安京の都の治安維持などにあたった。