On April 1, 1889, all cities in Japan were granted a municipality.

At this point, all mayors in Japan were appointed by the Ministry of Interior in Tokyo.

The first mayor of Hiroshima was Akira Miki, who remained in office for three months.

During the atomic attack on Hiroshima on August 6, 1945, mayor Senkichi Awaya was killed, and the municipal council had to appoint transitional mayor Shigetada Morishita, later followed by Shichirō Kihara.

Hamai and the mayors of Hiroshima that followed have tried to become leaders of international public opinion on issues such as peace and nuclear disarmament.