Baba Motoie served as a bushō for the Ukita clan in Bizen Province from the Sengoku period until the early Edo period.
Motoie resided in the village of Hokuchi in the Oku District of Bizen and served under Ukita Kunisada, the lord of Toishi Castle, participating in battles against Ukita Naoie. Naoie was the grandson of Ukita Yoshiie, Kunisada’s older half-brother. In 1534, Kunisada attacked Yoshiie at Toishi which led to Yoshiie taking his own life. Yoshiie’s son, Ukita Okiie, fled the castle with his son, Naoie, who was only six years old at the time.
During a battle in 1556, Motoie sustained an injury when an arrow shot by Hanabusa Masayoshi, a retainer of Ukita Naoie, pierced his middle finger, and he retreated. After his lord, Kunisada, perished in the battle, Naoie offered him 300 koku of rice in recognition of his military prowess.
In 1564, Motoie participated in the defense of Tatsu-no-kuchi Castle against invading forces from Bitchū Province.
In 1565, following an invasion by Mimura Iechika into Mimasaka Province, Motoie participated with the Uragami and Ukita armies in support of Gotō Katsumoto, lord of the mountain fortress of Mitsuboshi Castle, to successfully ward-off the attackers.
In 1567, Motoie made contributions at the Battle of Myōzen Temple against forces led by Mimura Motochika who invaded Bizen to seek revenge for his father, Mimura Iechika.
In 1570, Motoie joined with Togawa Hideyasu to seize Ishiyama Castle (known as Okayama Castle) after Kanamitsu Munetaka committed seppuku owing to a scheme by Naoie.
In 1580, when Motoie deployed for the battle of Taka Castle in Mimasaka, he incurred serious injuries when shot by an enemy arquebus. In 1582, he served in the rearguard at the Battle of Hachihama to defend against an invasion by the Mōri into Bizen. Later, he was honored as one of the Seven Spears of Hachihama.
During the period from 1586 to 1587, Motoie participated in the Kyūshū heitei, or Subjugation of Kyūshū, by forces under Toyotomi Hideyoshi. He was injured again, and owing to his old age, retreated to the town below the castle, tending the fields until his death of illness at age seventy-seven.