Kobayakawa Hideaki was the fifth son of Kinoshita Iesada and a nephew of Toyotomi Hideyoshi. He was gained the rank of Saemon no Kami (左衛門督) or in China Shikkingo (執金吾) at genpuku and held the court title of Chūnagon (中納言), Hideaki was also called Kingo Chūnagon (金吾中納言).

Toyotomi Hideyoshi , otherwise known as Kinoshita Tōkichirō and Hashiba Hideyoshi , was a Japanese samurai and daimyō of the late Sengoku and Azuchi-Momoyama periods and regarded as the second "Great Unifier" of Japan. Although he came from a peasant background, his immense power earned him the rank and title of Kampaku and Daijō-daijin , the highest official position and title in the nobility class. He was the first person in history to become a Kampaku who was not born a noble. He then passed the position and title of Kampaku to his nephew, Toyotomi Hidetsugu. He remained in power as Taikō (太閤), the title of retired Kampaku, until his death. It is believed, but not certain, that the reason he refused or could not obtain the title of shogun (征夷大将軍), the leader of the warrior class, was because he was of peasant origin.