As the Taira clan rose to power, Motomori was also assigned as kokushi (local governor) of a few provinces, including Yamato, Awaji, and Echizen, eventually reaching the title of Shoshiinoge (Senior Fourth Rank, Lower Grade), but he died young at the age of 24 in 1162.
以降平家一門の栄達に伴い、大和国、淡路国、越前国などの諸国司を歴任、正四位下まで昇進するが、応保2年に24歳にして早世した。