Lifespan: Tenbun 16 (1547) to 8/17 of Kanei 1 (1624)
Other Names: Shinshirō, Gorōemon, 遊甫 (monk’s name)
Lord: Shimazu Yoshihisa → Shimazu Yoshihiro
Father: Niiro Yasuhisa
Siblings: Matahachirō, Hisaatsu, Ryoan, Tadahide, sister (wife of Tajiri Tajima), sister (wife of Ijichi Shigemasa)
Adopted Children: Hisaaki
Niiro Hisaatsu served as a bushō from the Sengoku to early Edo periods. He was a retainer of the Shimazu clan of Satsuma Province. Hisaatsu served as the steward of 隈城 in Satsuma.
In 1547, Hisaatsu was born as the second son of Niiro Yasuhisa of an illegitimate branch of the Niiro clan.
In 1582, Hisaatsu fought against the Ryūzōji clan based in Higo Province. In 1583, he assaulted the Aso clan at Katashida Castle. In 1584, he captured Takaba Castle in Higo and, the following year, defeated the Kōshi clan of Higo.
In 1590, after Shimazu Yoshihisa received orders from Toyotomi Hideyoshi to conduct an expedition to the Ryūkyū islands, Hisaatsu was sent as a messenger upon orders of Yoshihisa.
In 1594, when Shimazu Tadatsune sailed to the Korean Peninsula for the Bunroku Campaign, Hisaatsu contributed by supplying provisions to soldiers who were struggling with hunger.
After a long life during a turbulent period, he died in 1624 at the age of seventy-eight.
When Francisco de Xavier, a Jesuit missionary from Spain traveled to Satsuma to conduct evangelical activities, he visited Hisaatsu’s father, Yasuhisa, at his base at Ichiki-Tsurumaru Castle. Hisaatsu, along with his mother and younger brother, Niiro Ryoan, received baptismal rites from de Xavier.