In the event of Eikyu no goso (violent plea in the Eikyu era) in 1113, Tadamori worked with his father Masamori to stop the troops of Kofuku-ji Temple coming into Kyoto.
永久(元号)元年（1113年）永久の強訴に父正盛とともに出動して興福寺の大衆の入京を阻止した。