Hiroyoshi was the son of Shiji Motoyoshi and first served Môri Okimoto. Following Môri Motonari's rise to the head of the Môri after 1523, Hiroyoshi became one of his most trusted advisors. An important administrator for Motonari, he assisted in the upbringing of Môri Takamoto. He was the elder brother of Kuchiba Michiyoshi.