When Prince Mochihito rose in arms in June 1180, Sukemori went off to war with a troop including his uncle, TAIRA no Tomonori, TAIRA no Shigehira, Koremori, his older brother, and they engaged in battle with MINAMOTO no Yorifusa at Byodoin Temple, where they destroyed the enemy forces.
治承4年（1180年）年5月の以仁王の挙兵に際して、叔父の平知盛、平重衡、兄の維盛らと出陣し、源頼政と平等院で戦いこれを滅ぼした。