His exact birth and death years are unrecorded. Takatoshi was a retainer of the Utsunomiya clan and a member of the Haga family, one of the two powerful warrior bands known as the "Kisei ryoto" (alongside the Mashiko). Serving his lord Utsunomiya Kagetsuna, he is said to have built Tobiyama Castle at a strategic point on the west bank of the Kinugawa River during the Einin era (1293-1298). While based there, the Haga family adopted the surname Kiyohara, said to be the origin of the present-day Kiyohara district of eastern Utsunomiya. The Haga clan went on to expand its influence as a senior retainer house of the Utsunomiya, later serving as shugodai (deputy military governor) of Kozuke and Echigo Provinces, though Tobiyama Castle itself was overrun by Southern Court forces during the turmoil of the Nanboku-cho wars. No primary source records his exact birth or death year; the years shown here are estimated from his lord Utsunomiya Kagetsuna's lifetime and the castle's construction period.