Lifespan: Unknown to 2/2 of Tenbun 2 (1533) (?) or the first month of Kyōroku 3 (1530)
Title: Governor of Etchū
Father: Nagai Hidehiro or Nagai Toshitaka
Children: Kagehiro, Inoue Michikatsu (?), Michitoshi (?)
Nagai Nagahiro served as a bushō during the Sengoku period. Nagahiro was the lord of Seki Castle and a vice-deputy governor of Mino Province.
Nagahiro was born as the son of either Nagai Hidehiro or Nagai Toshitaka. His real names were Toshimichi or Masatoshi, or Nagahiro (written with different characters). His common names included Tōzaemon-no-jō and Yajirō. He held the title of Governor of Etchū.
According to one theory, Nagahiro was the same individual as Nagai-Saitō Toshiyasu.
Upon the recommendation of Nichiun (the abbot of the Jōzai Temple and youngest son of Saitō Toshifuji), Nagahiro acquired as a retainer an oil merchant named Matsunami Shōgorō (the father of Saitō Dōsan). After the demise of the chief retainer named Nishimura Saburōemon Masamoto, the Nishimura clan separated from the Saitō. Nagahiro had Shōgorō inherit the surname of the Nishimura, giving him the name of Nishimura Kankurō (Masatoshi). Later, Kankurō adopted the Nagai surname and changed his name to Nagai Shinzaemon-no-jō (Bungo-no-kami). Through the support of Nagahiro, he became a cherished retainer of Toki Yoriaki.
Upon the death of Saitō Toshichika, the deputy military governor, his son, Saitō Toshiyoshi, was still a youth, so Nagahiro joined Nagai Toshitaka to support him. Initially, Nagahiro was the lord of Shirakashi Castle, but, to provide support to Toshiyoshi, he built and moved to a residence in the foothills of Mount Inaba. Thereafter, a struggle erupted in the Toki family concerning the successor to Toki Masafusa, the military governor of Mino. This occurred after Masafusa passed over his eldest son, Toki Yoritake, by designating his second son, Toki Yoriaki, to be his successor.
Saitō Toshiyoshi (the deputy military governor of Mino) backed Yoritake, while Nagahiro (the vice-deputy military governor) backed Yoriaki, leading, in 1517, to a battle. The faction supporting Yoritake prevailed, but, in 1518, Nagahiro and the other supporters of Yoriaki rolled-back their opponents. Turning for help from the original family of his wife, the Asakura clan, Yoritake and his wife and children fled to Echizen Province. According to documents at the Funyō Temple in Seki in Mino, the rights of the temple to their landholdings were recognized.
In 1519, after the death of Toki Masafusa, the Asakura clan dispatched troops to Mino to overthrow the faction supporting Yoriaki and succeeded in placing Yoritake in the role of military governor of the province. Nagahiro devised a plan to recapture political control and, in 1525, joined Nagai Shinazaemon-no-jō to raise arms, engaging in battle against Saitō Toshishige (who had become the new deputy military governor) and supporters of the Yoritake. The rebels attacked the main base of the Saitō at Inabayama Castle, and, in the sixth month, occupied the Fukumitsu residence of the military governor of Mino. Thereafter, the conflict with Yoritake persisted, and, in 1530, owing to a disadvantageous position, Yoritake fled again to Echizen. Thereafter, Yoriaki assumed in fact the role of the military governor while Nagahiro replaced the Saitō (the deputy military governors) as the holder of real authority in Mino.
On 1/23 of Kyōroku 3 (1530), owing to crimes of misconduct, Nagahiro and his wife were said to have been placed under the watch of Shinzaemon-no-jō. However, a prohibition signed by Nagai Nagahiro dated in the third month of the same year appears to refute this story. According to genealogical records of the Saitō family dated 2/2 of Tenbun 2 (1533), owing to collusion with Yoritake who had been ousted to Echizen, Nagahiro was killed by Shinzaemon-no-jō (or his son, Nagai Norihide) under the pretext of orders from the lord.
There is a document dated 11/26 of Tenbun 2 (1533) with the joint signatures of Nagai Kagehiro (Nagahiro’s son) and Nagai Norihide (Shinzaemon-no-jō’s son later known as Saitō Dōsan) noting that Kagehiro inherited the family out of deference to their lord’s family. In the ninth month of 1534, however, Norihide was prohibited from signing documents on his own, while Kagehiro’s name does not appear thereafter, so it is surmised that Kagehiro either died of illness or was killed by Norihide between 1533 and 1534.