Yoshihiro was the eldest son of Satomi Yoshitaka. He participated in the Uesugi encirclement of Odawara in 1561 and later met defeat at the Second Battle of Konodai. He afterwards allied with Takeda Shingen and battled with the Hôjô and Ota at Mifunedai (Mifuneyama) in 1567. He later sent troops by sea to Izu province to assist the Takeda's operations against the Hôjô in 1570. He died (evidently as the result of a stomach ulcer) without a son and so his younger brother Yoshiyori succeeded him.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005