Kazunaga Itō was born on 23 August 1945 in Nagato, Yamaguchi Prefecture, a week after the Surrender of Japan and two weeks after the atomic bombings of Hiroshima and Nagasaki. Itoh's family moved to his father's hometown of Nagasaki when he was three years-old. Itoh first aspired to become mayor of Nagasaki while attending Nishi Prefectural High School, and after graduating from Waseda University with a degree in political science began working for the Nagasaki City Development Corporation.