Lifespan: Tenshō 4 (1576) or eighth month of Tenshō 5 (1577) to 3/15 of Tenshō 20 (1592) (or 4/15 or 5/15)
Clan: Tozawa (descended from the Kanmu-Taira)
Lord: Toyotomi Hideyoshi
Father: Tozawa Michimori
Mother: Daughter of Hondō 親条
Siblings: Morishige, Moriyasu, Mitsumori
Wife: [Formal] Ōmori Gozen (daughter of Naraoka Mitsukiyo, younger sister of Mitsunobu)
Adopted Children: Masamori
Tozawa Mitsumori served as a daimyō during the Azuchi-Momoyama period. Mitsumori was the nineteenth head of the Tozawa clan and served as the lord of Kakunodate Castle in Dewa Province.
In 1576, Mitsumori was born as the son of Tozawa Michimori, the sixteenth head of the Tozawa clan based at Kakunodate Castle in Dewa.
In 1590, his older brother, Tozawa Moriyasu, while serving as the eighteenth head of the family, died early. Moriyasu’s son, Tozawa Masamori, was still an infant, so Mitsumori succeeded Moriyasu as the nineteenth head of the clan. During the Oushū Retribution conducted in the seventh and eighth months of 1590 by the Toyotomi administration, Mitsumori received official recognition of his rights to his landholdings. According to survey records of the Senboku District of Dewa, his recognized fief totaled 44,350 koku.
In 1592, after the start of the Bunroku Campaign on the Korean Peninsula initiated by Toyotomi Hideyoshi, Mitsumori headed toward Nagoya Castle in Hizen Province to participate, but, while en route, fell ill and, on 3/15 (or 5/15), died near Himeji in Harima Province at the age of seventeen. Under an alternate theory, he died on 4/15 in Akashi at the age of sixteen. According to legend, he died of smallpox in Shioya in Harima and was cremated along the shoreline in Shioya and interred at the Zenshō Temple. Worshipers visited his five-part gravestone representing earth, water, fire, wind and heaven to seek protection from smallpox.
Mitsumori was succeeded by his nephew, Tozawa Masamori.