Lifespan: 15xx to 16xx
Rank: bushō; chief retainer
Lord: Seki Narimasa → Shibata Katsuie → Gamō Ujisato → Gamō Hideyuki → Tōdō Takatora → Gamō Tadasato
Father: Saka Katsunori
Children: Satonobu, Satoie
Gamō Satonari served as a bushō from the Sengoku to early Edo period. Satonari was born the son of Saka Katsunori. He was the father of Gamō Satonobu and Gamō Satoie. Satonari was the chief retainer of the Gamō clan, serving numerous lords over his lifetime. He was commonly known as Genzaemon.
He was first named 坂源 Jirō, and, together with his father, Katsunori, served Seki Narimasa followed by Shibata Katsuie.
In 1583, after the death of Shibata Katsuie in the wake of the Battle of Shizugatake, Satonari became a rōnin, or masterless samurai, and then served Gamō Ujisato, the chief retainer of the Gamō clan. Satonari made contributions in an attack against Ganjaku Castle during the Subjugation of Kyūshū for which he was recognized by Toyotomi Hideyoshi, the kanpaku, or Chief Councilor to the Emperor. He was then permitted to use the Gamō surname and adopted the name of Gamō Satonari. In 1590, after the Gamō family was transferred by the Toyotomi administration to Aizu, Satonari served as the chamberlain of Ago-ga-shima Castle, and, later, for Shiroishi Castle. He then became the lord of Nihonmatsu Castle with a fief of 40,000 koku. Together with Gamō Satoyoshi, Satonari invited Sakuma Yasumasa and Sakuma Katsuyuki (two brothers known from the time serving the Shibata family who were rōnin, or masterless samurai) to serve as security forces.
In the sixth month of 1592, when Satonari was staying in Nagoya while Ujisato was deploying for the Bunroku Campaign on the Korean Peninsula, Satonari mediated a dispute between Gamō Satoyoshi and Gamō Satoyasu. After the death of Ujisato in 1595, Satoyasu murdered a servant named Watari Hachiemon. This caused Satonari to come into conflict with Satoyasu, whereupon Satoyasu was expelled from the family in an event known as the Gamō Disturbance.
Ujisato was succeeded by his eldest son, Gamō Hideyuki. Toyotomi Hideyoshi determined that Hideyuki was unable to halt a series of conflicts besetting the clan, so, in 1598, the Gamō family was demoted and transferred from Aizu (with a fief of 920,000 koku) to Utsunomiya in Shimotsuke Province (with a fief of 180,000 koku). The fief managed by Satonari was reduced to 30,000 koku and he became the lord of Kasama Castle in Hitachi Province. Further, after the ouster of Satoyasu, he served as one of the magistrates for the Oushū Retribution on behalf of the Toyotomi.
In 1601 (the year following the Battle of Sekigahara), Hideyuki returned to Aizu with a fief of 600,000 koku. Satonari served as the chamberlain at Moriyama and Miharu castles, and then became the lord of Sukagawa Castle while his fief was increased to 45,000 koku. Thereafter, he came into conflict with Oka Shigemasa (the chief retainer of the Gamō family) and, together with his sons, Satoie and Satonobu, fled the Gamō family and entered the service of Tōdō Takatora, a daimyō based in Imabari in Shikoku who received an increase to his fief after fighting for the Eastern Army at the Battle of Sekigahara.
In 1612, Hideyuki suddenly died at the age of thirty and was succeeded by his eldest son, Gamō Tadasato, at the age of ten. Hideyuki’s widow, Furihime (the third daughter of Tokugawa Ieyasu) served as his guardian. She then came into a severe conflict with Shigemasa over matters of governance of the domain which culminated in her father, Ieyasu, summoning Shigemasa to Sunpu Castle and ordering him to commit seppuku. Thereafter, Satonari, along with his sons (Satoie and Satonobu), returned to the service of the Gamō family upon request of Tadasato. Satonari died of illness en route to Aizu to their return to service, so Satonobu received a fief of 30,000 koku while Satoie received Miharu Castle and a fief of 15,000 koku.