Obara Akimoto served as a bushō during the Azuchi-Momoyama period.  He was a retainer of the Ōtomo clan.

The Obara clan was an illegitimate branch of the Anan clan from Obara in the Anan manor in the Oita District of Bungo Province.

Akimoto was born as the son of Obara 右並, a retainer of the Ōtomo clan, the sengoku daimyō of Bungo.  Initially, he served Ōtomo Yoshiaki, the twentieth head of the clan.  He received one of the characters from the name of Yoshiaki and adopted the name of Akimoto.

In 1550, during an assault against Yoshiaki and his family by retainers in an event known as the Collapse on the Second Floor, Akimoto, along with Ogi Harukage, Yoshioka Nagamasu, Takita Akinari, Usuki Akitsugu, and Shiga Chikamori jointly signed the last will and testament of Akimoto.  Thereafter, Akimoto became a member of a senior council (known as the kahanshū) to Akimoto’s son, Ōtomo Yoshishige (Sōrin).  That same year, owing to tumult within the Ōtomo family, Akimoto joined Saeki Korenori to attack Kikuchi Yoshitake at Kumamoto Castle and pacified Higo Province.  In 1551, he entered Nankan Castle and divided Higo with an enemy.

In the fifth month of 1556, during an event known as the Confrontation of Surnames, family members with a surname and crest other than Ōtomo rallied together to raise arms against important policies of the branch families who carried the Ōtomo surname.  Friction between the two groups existed within the clan from an earlier time, so Ōtomo Yoshiaki had pledged in his last testament that one-half of the council of clan elders, known as the kahanshū, would be chosen from the group who carried a surname other than Ōtomo.  However, his son, Ōtomo Yoshishige, the twenty-first head of the clan, favored a council of elders with the Ōtomo surname, so senior retainers such as Akimoto were removed from the council.  In the case of Akimoto, this occurred despite his contributions to pacify Higo Province.

The revolt by members of the family with a surname other than Ōtomo also occurred near the primary residence of the Ōtomo clan in Funai.  This caused Yoshishige to take refuge in the stronghold of Usuki Castle for a while, but members of the clan who carried the Ōtomo surname fought back and killed Honjō Shinsaemon-no-jō Munetsuna, Nakamura Shinhyōe Naganao, and Kaku Kii-no-kami Koreshige, while Saeki Korenori fled to Iyo Province in Shikoku.  Intrepid commanders such as Akimoto sheltered in Nankan Castle and exhorted the defenders to fight valiantly, but the attackers set fire to the castle, and after tending to the women and children, Akimoto joined his men to rush out of the castle and perish in battle.