Bekki Chikamune served as a bushō and member of the Bekki clan, a branch of the Ōtomo clan, sengoku daimyō of Bungo Province.   Chikamune carried the titles of Senior Assistant Minister of Civil Affairs and Assistant Vice-Minister of Civil Affairs.

Chikamune was the son of Bekki Chikanobu.  In 1551, Chikanobu died in the Battle of Osaka in Hizen Province, after which Chikanobu’s younger brother, Chikatsugu, became head of the clan.  Chikamune and his older brother, Bekki Chikashige, were adopted by Chikatsugu.

In 1535, Chikamune deployed to Higo Province under the guardianship of Bekki Akitsura (later known as Tachibana Dōsetsu) in response to a rebellion by the Kikuchi clan and other kokujin.  At the Battle of Kurumagaeshi, Chikamune served in the vanguard attacking the mounted soldiers of the enemy.  Chikamune’s furious combat stirred the spirits of his fellow soldiers on the battlefield.  During the Eiroku era (1558-70), Chikamune served along with his older brother, Chikashige, as a commander under Akitsura in the Ōtomo army, including a series of five battles at Moji Castle in Hizen Province spanning from 1558 to 1562.  He also participated in attacks against Takahashi Akitane at his home base of Hōmanyama Castle.

In 1567, Chikamune deployed to Chikuzen Province in an attack against the Akizuki clan.  He died in a preliminary skirmish during an attack on Yu Castle prior to the Battle of Yasumimatsu.