Hayashi Narinaga was a samurai during the Sengoku period, retainer of the Mōri clan and was a ji-samurai (koku-jin-ryōshū) of southern Bingo Province. He held many positions including karō serving Mōri Motonari and his father Mōri Hiromoto in diplomatic missions with Toyotomi Hideyoshi. Narinaga was a bugyō under Mōri Terumoto. From Hideyoshi he received the rank of Hizen-no-kami (肥前守). He served as diplomat between the Mōri and Hideyoshi. Later he was bestowed the 5th court rank, junior grade Ju go-i-no-ge (従五位). The character "nari, 就" came from his lord Mōri Motonari and "naga, 長" from his father Kikuchi Takenaga. Narinaga was one of the few to live through all the Sengoku period.

The Mōri clan was a Japanese samurai clan descended from Ōe no Hiromoto. Ōe no Hiromoto was descended from the Fujiwara clan. The family's most illustrious member, Mōri Motonari, greatly expanded the clan's power in Aki Province. During the Edo period his descendants became daimyō of the Chōshū Domain under the Tokugawa shogunate. After the Meiji Restoration with the abolition of the han system and daimyō, the Mōri clan became part of the new nobility.