Hamanari was also a poet like his father who was a Manyo kajin (poet of Manyoshu), and presented the oldest existing book on poetry in Japan, "Kakyo Hyoshiki (A formulary for verse based on the canons of poetry)" to Emperor Konin.
万葉歌人であった父麻呂の血を受け継いで、浜成も歌人であり、現存する日本最古の歌学書である『歌経標式』を光仁天皇に撰上している。