After his father was killed by Suketsune Kudo, his mother married Sukenobu Soga.
He and his younger brother, Tokimune, killed Suketsune on the night of May 28, 1193 in his lodging at the foot of Mount Fuji. Suketsune was participating in a hunting party of Yoritomo Minamoto. After the brothers revenged themselves on then father's enemy, they were besieged by Yoritomo's troops. Sukenari was killed by Tadatsune Nitta and Tokimune was captured and later executed. Sukenari's wife, Tora, who was a courtesan at Qiso (Kanagawa Prefecture), became a nun at his death. The Soga brothers' vendetta is celebrated in stories and drama.