Seiwa-Genji was considered to be the top of the military families because it produced successive shogun during the Kamakura period, an extremely large number of military families, such as Ashikaga and Tokugawa who produced samurai, and claimed to be descendants of Seiwa-Genji.
鎌倉将軍一覧を輩出したことから、武家の統領の家柄とされ、足利氏・徳川氏の両将軍家を初めとして、極めて多数の武家が清和源氏の子孫と称した。