In 1051, Yorito, together with his son MINAMOTO no Arimitsu, went to Oshu (Northern Honshu, the region encompassing Mutsu and Dewa provinces) following the Governor of Mutsu Province, MINAMOTO no Yoriyoshi, to serve in Zen Kunen no Eki (Former Nine Years' Campaign.)
永承6年（1051年）、頼遠は子の源有光とともに陸奥守源頼義に従って奥州に下向、前九年の役に従軍した。