Sagae Tomohiro served as a bushō during the Sengoku period.  He was the thirteenth head of the Sagae clan.  He was the sixth lord of Sagae Castle in the Sagae manor of the Murayama District of Dewa Province.

Tomohiro was born as the eldest son of Sagae Tamehiro, the twelfth head of the Sagae.  In 1486, after the demise of his father, Tomohiro inherited the headship of the clan.

In 1489, he donated lands to the Tainei Temple in Nagato Province and built the Chōkō sub-temple.  This was intended for the worship of both parents.  At the time, his father’s uncle, Zengan Tōjun, was serving as the seventh abbot of the Tainei Temple.  That same year, he engaged in the reconstruction of the Ōnuma-Daigyō Temple.

On 7/28 of Meiō 3 (1494), Tomohiro died and was succeeded by his eldest son, Sagae Munehiro.  After Tomohiro’s demise, his widow requested to move to Sagae and renamed the Chōkō sub-temple to the Zuiryūsan-Chōkō Temple.