Sagoshi Ujifusa served as a bushō during the Sengoku period. He was the lord of Sagoshi Castle in the Akumi District of Dewa Province.
Ujifusa was either the younger brother or son of Daihōji Ujimasa, a bushi and the twelfth head of the Daihōji clan.
The Sagoshi originated as an illegitimate branch of the Daihōji clan. The Sagoshi were kokujin, or provincial landowners, serving as governors of the Akumi District. In 1512, the head of the clan, Sagoshi Ujitaka, invaded the Tagawa District and defeated Daihōji Sumiuji, the thirteenth head of the Daihōji, in a major battle. In 1513, he invaded the Tagawa District a second time but lost and, along with his son, was killed in action. This ended the bloodline of the Sagoshi clan.
Sagoshi Castle was in a strategic location in the Akumi District so, in 1518, Ujifusa was assigned to become the chamberlain of the castle. Although a member of the Daihōji family, owing to this assignment, Ujifusa adopted the Sagoshi surname and endeavored to revive the Sagoshi family.
In the course of governing the territory of Sagoshi, Ujifusa began to resent the rule of the Daihōji and gradually leaned toward independence. In 1533, Ujifusa rebelled against Daihōji Harutoki, the fifteenth head of the main branch of the family. This resulted in the burning down of Daihōji Castle. In a bid to resolve the conflict, Harutoki then turned to the Uesugi in neighboring Echigo Province. Through mediation by the Uesugi clan of Echigo, a tentative settlement was reached, but, the next year, this was scrapped and the two sides clashed again. Thereafter, perhaps because the Sagoshi submitted, the Uesugi facilitated a settlement between the Daihōji and multiple dogō, or wealthy families, in the province.
Later, the Sagoshi clan frequently continued to resist the Daihōji, but, after losing to the Mogami clan at the Battle of Jūgorigahara, the Sagoshi followed the Akita clan and departed from thew territory of Sagoshi.