He fought against the brothers of KO no Moronao and KO no Moroyasu of the Ashikaga side in the Battle of Shijonawate which took place at Hojo, Kawachi Province (Shijonawate City, Osaka Prefecture, as of now) in 1348, but he was defeated and committed suicide with his younger brother, Masatoki KUSUNOKI, by stabbing each other (there are various opinions about his age of death).
正平(日本)3年/貞和4年（1348年）に河内国北條（現在の大阪府四條畷市）で行われた四條畷の戦い（四條縄手）において足利方の高師直・高師泰兄弟と戦って敗北し、弟の楠木正時と刺し違えて自害した（享年に関しては諸説がある）。