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.

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.

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.

Sagae has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 16 members.

East Japan Railway Company - Aterazawa Line Media related to Sagae, Yamagata at Wikimedia Commons