Thereafter, he overthrew Yoshikazu HIKI, Yoriie's maternal relative, in cooperation with his father Tokimasa in the Yoshikazu HIKI Incident in 1203, and assassinated Yoriie the following year.
その後、父時政と共に1203年、比企能員の変で頼家の外戚比企能員を滅ぼし、翌年頼家を暗殺した。