There were two individuals with the name of Fukubara Sadatoshi who originated from the Ōe family affiliated with the Aki-Fukubara clan.

The first Fukubara Sadatoshi served as a bushō during the Sengoku period and a retainer of the Mōri clan.  He was the ninth head of the Aki-Fukubara clan.  He was the son of the eighth head of the clan, Fukubara Hirotoshi.  His younger brother was Fukubara Motozumi.  His younger sister became the formal wife of Mōri Hiromoto who gave birth to Mōri Okimoto and Mōri Motonari.  Sadatoshi was the father of Fukubara Hirotoshi, the tenth head of the clan (of the same name as the eighth head of the clan) and a veteran of the Mōri clan.

The second Fukubara Sadatoshi served as a bushō during the Sengoku period and a retainer of the Mōri clan.  He was the eleventh head of the Aki-Fukubara clan.  Sadatoshi was the eldest son of Fukubara Hirotoshi, the tenth head of the clan.  He was the grandson of the first Fukubara Sadatoshi noted above.  Hirotoshi inquired with Mōri Motonari about succession plans, reflecting the influence of the Fukubara within the Mōri family.  From early on, Sadatoshi served Motonari, engaging in numerous battles.  In 1550, Sadatoshi’s military contributions and faithful character earned the trust of Motonari so that he was elevated to the role of chief retainer in the Mōri clan.

In 1555, after the Battle of Itsukushima, in the Subjugation of Bōchō, a conflict in which the Mōri invaded the territory of the Ōuchi clan in Suō and Nagato provinces, Sadatoshi participated in the siege of Katsuyama Castle in Nagato after which Ōuchi Yoshinaga and Naitō Takayo were compelled to take their own lives.  Thereafter, Sadatoshi joined with Kobayakawa Takakage to launch military operations centered around the Seto Inland Sea.  In 1567, Sadatoshi led the main division in the Deployment of the Mōri to Iyo and, in 1569, in the Ōuchi Teruhiro Conflict.

Following the death of Motonari, Sadatoshi served as an advisor to Mōri Terumoto, and, together with Kikkawa Motoharu, Kobayakawa Takakage, and Kuchiba Michiyoshi, was known as one of the Group of Four.  Sadatoshi was primarily responsible for supporting Takakage and for managing political and military affairs in the Sanyō and Seto Inland areas.

In 1584, owing to his advanced age, Sadatoshi transferred the role as head of the family to his eldest son, Fukubara Mototoshi, and retired.  He died in the summer of 1593 at the age of eighty-two (or seventy-five).  In the Edo period, his descendants served as elders of the family for the Chōshū domain.

During the Sengoku and Azuchi-Momoyama periods, multiple individuals with the names of Hirotoshi, Sadatoshi, and Mototoshi served as heads of the Fukubara clan.