He is considered a son of busho, Iehiro SHO, who was thought to have built his own mansion in Kurisaki Village, Oyose-go, Kodama-gun, Musashi Province, and Ienaga's heroic stories can be seen in "Azuma Kagami" (The Mirror of the East) and Genpei Seisuiki (The Rise and Decline of the Minamoto and Taira clans).
庄太郎家長は、武蔵国児玉郡大寄郷栗崎村（現在の大字栗崎）の地に館を築いたとされる武将庄家弘の子とされ、彼の活躍は、『吾妻鏡』や『源平盛衰記』に記されている。