The Kawachi Genji (河内源氏) were members of a family line within that of the Seiwa Genji, which in turn was one of several branches of the Minamoto clan, one of the most famous noble clans in Japanese history.

Minamoto no Yorinobu, the founder of the Kawachi Genji, was the third son of Minamoto no Mitsunaka, who put down the Taira no Tadatsune Rebellion and established his power in the Kanto region, and during the time of his son Minamoto no Yoriyoshi and Yoriyoshi's son Minamoto no Yoshiie (Hachiman Taro Yoshiie), they brought some of the Kanto samurai under their control during the Former Nine Years' War and the Later Three Years' War, and during the time of Yoshiie, he came to be regarded as the head of the samurai family.

Yoriyoshi married the daughter of Taira no Naokata and inherited the direct power of the Bando-Heishi clan (and Kamakura).

However, immediately after that, Kawachi Genji's relationship with the Emperor and the aristocracy deteriorated.

While taking advantage of the value of the Kawachi-Genji branch, Minamoto no Yoritomo won the Genpei War, opened the Kamakura shogunate, and was appointed as Seii Taishogun.