From the earliest times, the fertile region around Saijō (part of the ancient province of Aki) has been occupied, as displayed by the Mitsushiro Kofun (a 5th-century burial mound) and the Aki-Kokubunji (Aki-Kokubun temple) from the 8th century.

[citation needed] During the later Edo period, Saijō was a post-town on the San'yōdō and home to a government office.

In 1974 the Kamo District towns of Saijō, Hachihonmatsu, Shiwa and Takaya were combined to form Higashihiroshima, the twelfth city in Hiroshima Prefecture.

The relocation of the university and the establishment of the Hiroshima Central Technopolis (since 1984) has created many jobs and intellectual opportunities, a new communications network (Saijō was made part of the Sanyo Shinkansen in October 1993) and has put the area on the technology map, but has also seen much of the green-field areas eaten up as the population of Higashihiroshima City soared to 100,000 (August 1992).

Within the narrow streets of the Sakagura Dori ("Sake Storehouse Road") area near JR Saijō Station are the Namako wall (white-lattice walled) and Sekishu Gawara [ja] (red-roof tile) roofs of ten well-known sake breweries; Chiyonoharu, Fukubijin, Hakubotan, Kamoki, Kamoizumi, Kamotsuru, Kirei, Saijotsuru, Sakurafubuki, and Sanyotsuru.