However, with Shigemori being ousted Munemori was forced to take the front stage; and, in April 1178, he was appointed to the position of supernumerary chief councillor of state.
しかし、重盛が事実上の失脚状態となったことで表舞台に立たざるを得ず、翌治承2年（1178年）4月、権大納言になる。