Miyahara Kageharu served as a bushō from the Sengoku to early Edo periods. He was a retainer of the Satsuma-Shimazu clan. In later year, he adopted the surname of Nire and the the monk’s name of Shūsen.
Kageharu’s older brother, Miyahara Kagetsugu, was the adopted son-in-law of Miyahara Kagetane, but, in 1568, he was killed in battle against the Hishikari clan. Consequently, as the younger brother, Kageharu became the adopted son-in-law. In 1578, he served meritoriously in an attack against Niiroishi Castle. After becoming the steward of Kushikino, he participated in the assault against Minamata Castle in 1581 and in the Siege of Iwaya Castle in 1586.
Thereafter, Kageharu served as a chief retainer of Shimazu Yoshihiro as well as the steward of Kamiya and Akune. In 1599, Kageharu was assigned as a magistrate for the construction of Shingaku Temple and, while overseeing the construction of Takaono Castle in Izumi, was appointed as the steward of Izumi.
In 1618, Kageharu’s eldest son and designated heir, after conducting a survey of the Ryūkyū islands, Miyahara Kagehira drowned when his boat sank during the return voyage. In 1620, when receiving Nire Yorikage (the son of Mihara Shigesada) as the adopted son-in-law of Kagehira, changed his surname to the Nire clan.
In 1642, Kageharu died of illness in Takaono in Izumi.