Lord of Mito in Hitachi Province, feared as 'Oni Yoshishige' (Demon Yoshishige) and the most powerful force in northern Kanto. Combining martial prowess with shrewd strategy, he built an extensive domain across northern Kanto including Hitachi, Shimotsuke, and Kozuke. He sent his second son Satake Yoshihiro (later Ashina Yoshihiro) to the Ashina of Aizu as an adopted heir, aiming to extend his influence into southern Oshu. Wary of Date Masamune's southward expansion, he led and coordinated an anti-Date coalition in southern Oshu that included the Soma, Iwaki, Ashina, and Nihonmatsu clans. However, in 1589 at the Battle of Suriagehara, his own biological son—now heading the Ashina—suffered a catastrophic defeat at the hands of Date Masamune, and Yoshishige lost all influence in Oshu. At Sekigahara (1600) he leaned toward the Western army and was punished after the battle by a drastic transfer from 540,000 koku in Hitachi to 200,000 koku in Kubota (Akita) in Dewa Province. Yet in his new domain he devoted himself to the administration of agriculture, forestry development, and land surveys, and was deeply loved by his people as a wise ruler. He died in 1612 in Mito.

Known as a fierce warrior in keeping with his fearsome epithet, he was equally skilled in diplomacy and governance. He led a broad regional coalition stretching from northern Kanto into Oshu, showing considerable political acumen.

After his transfer to Akita, he built the foundation of the 200,000-koku Satake domain and promoted agriculture and forestry. Highly regarded for his contributions to Akita's development. The contrast between his fearsome military reputation in Mito and his benevolent rule in Akita is often noted. The Satake continued as lords of Akita domain until the Meiji era.