Yoshiaki was the eldest son of Satake Yoshiatsu. He invaded the lands of the Yûki and defeated an allied Yûki-Ashina army. Some time later, he married his daughter to the young Utsunomiya Hirotsuna, who had been expelled from his domain in Shimotsuke by the Nasu family. Yoshiaki was able to reclaim Hirotsuna's domain and establish the latter there around 1557, in the process increasing the Satake's own domain. The next year he defeated Oda Ujiharu. Following a campaign against the Sôma, Yoshiaki's health began to fail him and he handed over leadership of the family to his eldest son Yoshishige in 1562.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005