Hiromoto's second son, Hirotoki NAGAI became a provincial constable of Bingo Province, and his descendants, at least from his son, Yasuhide NAGAI, filled critical posts in the Kamakura bakufu such as a member of Council of State as a direct blood line of the Oe clan after his elder brother, Chikahiro lost his position in the Jokyu Disturbance.
次男・長井広時は備後守護となり、兄大江親広が承久の乱でその地位を失って以降、大江氏の嫡流として、少なくともその子長井泰秀から評定衆を始め幕府の要職を務めた。