He fought successfully in "Genpei Seisuiki" (Rise and Fall of the Minamoto and the Taira clans) as one of the Four Great Retainers of MINAMOTO no Yoshitsune, along with his brother Morimasa, and in the Battle of Yashima, he fought against TAIRA no Noritsune at Ichiobata and was killed.
『源平盛衰記』では兄盛政と共に義経四天王の1人として活躍し、屋島の戦いにて、射落畠で平教経と戦い討死する。