With assistance of Kenshin UESUGI who was Shugo (provincial constable) of Echigo and Kanto Kanrei (a shogunal deputy for the Kanto region), he was able to expel Yoshiuji ASHIKAGA, which enabled him to enter Koga Imperial Palace and become Kogakubo for a period of time (he was not included among the successive kubos).
越後の守護で関東管領でもあった上杉謙信の助力により足利義氏を追放し古河御所に入ることができ一時期古河公方となった（歴代には数えず）。