Born a son of Ashikaga Sadauji, one year younger than his full brother Takauji, with whom he shared a strong bond.
With his brother he helped topple the Kamakura shogunate. Under the Kenmu Restoration he escorted Prince Nariyoshi to Kamakura and governed the Kantō.
Attacked by Hōjō Tokiyuki, he fell back from Kamakura; the Taiheiki says he had Prince Moriyoshi, confined there, put to death. His brother Takauji came to his aid and retook Kamakura.
Entering Kyoto with his brother, he helped draft the Kenmu Code, the new shogunate's guiding principles.
When Takauji became shogun, Tadayoshi handled justice and administration. Earnest and principled, he valued the old order; this is called the brothers' "dual rule".
He clashed bitterly with the steward Kō no Moronao, who sought to expand lands by new force. Moronao besieged his mansion and forced him out of government; he took vows.
He slipped out of Kyoto, allied with the Southern Court and raised troops, splitting the shogunate in two (Kannō Disturbance).
He defeated his brother's army at Uchidehama in Settsu, and Kō no Moronao was killed. The brothers briefly reconciled, but fell out again, and Tadayoshi moved to Kamakura.
Defeated by his brother's army, he surrendered, was confined in Kamakura, and soon died; some say he was poisoned. So ended the brothers' feud.
Kō no MoronaoAshikaga Yoshiakira
Sasaki DōyoKō no MoronaoNitta YoshisadaAshikaga TakaujiNijō YoshimotoImagawa Sadayo (Ryōshun)Hosokawa YoriyukiAshikaga Yoshiakira
People of the Muromachi period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.