Mogami clan
The area of present-day Sagae was part of ancient Dewa Province, and has been settled since prehistoric times, with numerous archaeological findings from the Japanese Paleolithic through the Kofun periods. In the late Heian through Kamakura periods, it was a "shōen" under the control of the Ōe clan. The Ōe were destroyed by the Mogami clan in the Sengoku period, who were in turn destroyed by the Tokugawa shogunate in the early Edo period. The territory was administered as "tenryō" under direct control of the shogunate until the Meiji Restoration, and was briefly a battleground in the Boshin War. After the start of the Meiji period, the area became part of Nishimurayama District, Yamagata Prefecture. The village of Sagae was established on April 1, 1889 with the creation of the modern municipalities system, and was raised to town status on January 7, 1893. It became a city on August 1, 1954.