He had served the Ashikaga shogunate since the period of the fourth shogun Yoshimochi ASHIKAGA; he served at Samurai-dokoro (the Board of Retainers), and was assigned as shugo of Yamashiro Province in 1418 and in 1434, and became a dominant shugo daimyo of four provinces, Mikawa, Wakasa, Tango and Yamashiro (besides those posts he was appointed bungun-shugo [provincial constable of specially given province] of Kaito County and Chita County of Owari Province).
4代将軍足利義持時代から仕え、侍所を務め、1418年、1434年には山城国の守護にも任じられ、三河国・若狭国・丹後国、そして山城の4カ国（他に尾張国海東郡・知多郡分郡守護）を兼ねる有力守護大名となった。