Born as a son of Tokiko, the legal wife of Kiyomori, Shigehira was conferred with a Court rank from his infancy, promoted smoothly as a Kindachi (children of nobles) of the Taira clan and appointed to the position of Sakone gon no chujo (Provisional Middle Captain of the Left Division of Inner Palace Guards).
正妻の時子の子として生まれた重衡は幼少にして叙位し、平氏の公達として順調に昇進を重ね、治承3年（1179年）には左近衛権中将に進んだ。