The Mori clan was founded by Yorisada MORI, who was the second son of MINAMOTO no Yoritaka, himself the third son of Yoshitaka (for more detailed biographies of Mori family members, please consult the page on the Mori clan).
森氏は義隆の3男・源頼隆の次男・森頼定に始まる（家伝の詳細は森氏の項を見よ）。