Hamada was born near Daikokucho Station in Naniwa-ku, Osaka to Kengoro and Nobuko Hamada. His family moved to Amagasaki, Hyōgo Prefecture before entering a kindergarten. There, he attended Ushio Elementary School and met Hitoshi Matsumoto. He and Matsumoto did not become friends until junior high. Like Matsumoto, his family was very poor and lived in an old, run-down apartment building.
