Born a son of Hosokawa Mochiyuki of the Hosokawa house, which served as kanrei (deputy shogun).
The year after the Kakitsu Incident his father died, and as a boy he inherited the Hosokawa house, supported by kin and retainers.
In his mid-teens he became kanrei; he held the post three times for long periods, standing at the center of shogunal government.
Around this time he married an adopted daughter of the powerful governor Yamana Sōzen and allied with him; together they dealt with problems in the Akamatsu and Hatakeyama houses.
He founded the Zen temple Ryōan-ji in Kyoto; its famous rock garden is thought to date from a later age. Katsumoto was a cultivated man versed in waka, painting and even medicine.
He helped restore the Akamatsu house, destroyed after the Kakitsu Incident. Sōzen, who had gained former Akamatsu lands, resented this, and relations between the two soured.
His heir Masamoto was born.
Over the succession disputes of the shogunal house and the Hatakeyama, his rift with Sōzen became decisive. As commander of the Eastern Army, Katsumoto held the Palace of Flowers where the shogun lived. Over 200,000 troops of both sides are said to have gathered in Kyoto.
With the war dragging on, Sōzen died that year and Katsumoto died of illness about two months later, in his early forties. Fighting continued for some time after both were gone.
Yamana SōzenHatakeyama MasanagaHosokawa MasamotoAsakura Takakage (Toshikage)Ashikaga YoshimasaAshikaga Yoshimi
RennyoSesshūSōgiAsakura Takakage (Toshikage)Ōta DōkanAshikaga YoshimasaAshikaga YoshimiHino Tomiko
People of the Muromachi period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.