When the Hogen War occurred thereafter, his eldest brother Tameshige sided with the Retired Emperor Sutoku (according to "Sonpi Bunmyaku" [a text compiled in the 14th century that records the lineages of the aristocracy]), and Kageshige joined the army of Emperor Goshirakawa as a vassal of MINAMOTO no Yoshitomo.
その後の保元の乱では、長兄の為重が崇徳上皇方に与したとされる一方で（『尊卑分脈』）、景重は源義朝の郎党として後白河天皇方に参陣。