Unno Munetsuna served as a bushō during the Sengoku period. Munetsuna was a member of a gōzoku, or wealthy family, in Shinano Province. He was the head of the Unno family, a lineal branch of the Three Families of the Shigeno (the Unno, the Nezu, and the Mochizuki) which, from long before, governed eastern Shinano. The Unno were based at Taiheiji in the Unno manor in the Chiisagata District.
Munetsuna was born as the son of Unno Yukimune. Sanada Yukitsuna was the son of Munetsuna’s daughter. Under another theory, Yukitsuna was the husband of Munetsuna’s daughter.
In 1527, Munetsuna sent a contract to the Rengejō Temple for lodging during a visit to Mount Kōya by the Unno family.
Through the assistance of the Yamanouchi-Uesugi family, the deputy shōgun of the Kantō, Munetsuna led a small contingent of family members including Sanada Yukitsuna to flee to Kōzuke Province. Upon request of Munetsuna, he is surmised to have accompanied Nagano Narimasa, the lord of Minowa Castle, on a deployment to the Saku District but was unable to recover his territory.
Owing to a lack of authenticated sources, the year of his demise is uncertain. According to one theory, Munetsuna was under the protection of the Haneo clan from the lineage of the Unno clan in the Agatsuma District of Kōzuke. Later, the sons of Haneo Yukiyasu, Haneo Yukiaki and Haneo Teruyuki, succeeded Munetsuna and adopted the Unno surname.