In 1361, Masanori succeeded in the third regaining of Kyoto together with Kiyoji HOSOKAWA, former steward of the bakufu (Japanese feudal government headed by a shogun), who had been overthrown due to political strife in the Muromachi shogunate (Koan Coup) and come to subject to the Southern Court, and so on, but they had to withdraw the next month.
正平16年/康安元年（1361年）、室町幕府の政争（康安の政変）で失脚し南朝に降った元幕府執事の細川清氏らとともに、三度目の京都奪還に成功するが、翌月には撤退している。