Awaya Motomichi served as a bushō and retainer of the Mōri clan of Aki Province in the Sengoku and early Edo periods.

Motomichi was the son of Awaya Motomune and grandson of Awaya Motohide.  His younger brother was Awaya Narinobu.

In 1537, Motomichi held his coming-of-age ceremony and received one of the characters in his name from Mōri Motonari.  In 1548, he participated in his first deployment, an attack against Kannabe Castle in Bingo Province.  Motomichi further joined the Bōchō keiryaku, an offensive by Motonari against the Ōuchi clan in Suō and Nagato provinces.  This included an invasion into Kudamatsu and the Battle of Susumanuma Castle., followed by attacks in Iyo Province from 1567 to 1568.  Based on these contributions, he served as a daikan, or magistrate, in Iwakuni in Suō Province.  Motomichi was included in the group of elders pursuant to the Mōri internal rules in 1572.  He engaged in battle against the Ukita clan, and, together with Katsura 就宣 served as the commander in charge of defending Iiyama Castle in Bitchū Province.  Scribbled writings remain in the Buddhist prayer hall of the Hōmyō Temple below the castle.  Upon request of Mōri Motonari, the Meiishiyama-Yahata Shrine was rebuilt in 1533.  The shrine contains a ceremonial dragon head donated by Motomichi at the time of its opening. In 1585, Motomichi assigned the role of head of the Awaya clan to his eldest son, Motosada, dying in 1607.