Ishimoda Mitsuyori was a hereditary senior retainer of the Date clan and head of the Ishimoda family, whose seat was Ishimoda Castle in Date district, Mutsu Province. He served as a magistrate (bugyo) under both Date Tanemune and Date Harumune, fighting on Harumune's side in the Date clan's internal war, the Tenbun Disturbance, which began in 1542. After the war ended in Harumune's favor in 1548, Mitsuyori secured his position as lord of Ishimoda Castle; in 1553 Harumune confirmed his holdings over several villages including Ishimoda, and he received the court rank of Junior Fifth Lower and the title Awa no Kami from shogun Ashikaga Yoshiteru. His heir Kageyori was born at Ishimoda Castle in 1559.

A steadfast hereditary retainer who backed the winning side in his lord's internal war and supported the Date clan's administration as a magistrate.

The Ishimoda family, continuing through Mitsuyori and his son Kageyori, supported the Date clan until 1591, when Date Masamune's transfer to Iwadeyama led to the confiscation of Date district and the loss of their position at Ishimoda Castle. Kageyori's line later inherited the Koori family name and survived as a Date-affiliated house.