Bessho Harusada served as a bushō of the Bessho clan in eastern Harima Province.
Harusada was a member of the vanguard of Bessho forces, often assigned to conduct ambushes. In 1579, upon orders from his older brother, Bessho Nagaharu, Harusada and his uncle, Bessho Yoshichika, led 800 soldiers on a surprise attack against forces under the command of Hashiba Hideyoshi at Mount Hirai. This was aimed at securing supply lines which had been severed by the Hashiba army during the Siege of Miki. The attack failed and Harusada was killed in action by a retainer of the Hashiba named Higuchi Masakane.