Hayashi Narinaga (林 就長, 1517 – July 19, 1605) was a samurai during the Sengoku period, retainer of the Mōri clan and was a ji-samurai (koku-jin-ryōshū) of southern Bingo Province.

The character "nari, 就" came from his lord Mōri Motonari and "naga, 長" from his father Kikuchi Takenaga.

[1 1] Hayashi Narinaga was born 1517 in Doi (土), Kawajiri (川尻), Bingo Province, today part of Mihara City, Hiroshima Prefecture.

His father was Kikuchi Takenaga (菊池武長) and his mother is unknown but there is a tradition that she was a daughter of the Hayashi clan of Kawajiri.

[8] In July 1562 at the First Siege of Toda Castle, Mōri Motonari ordered Hayashi Narinaga to go as a messenger to Honjō Etchū-no-kami Tsunemitsu (本城常光).

Honjō Tsunemitsu held Yamabuki Castle (山吹城) in Iwami Province and was originally a vassal of the Amago clan, but defected to Mōri Motonari in 1563.

When it fell to Mōri Motonari, Katsuhisa committed suicide (seppuku) and his loyal and heroic general Yamanaka Yukimori was captured and killed in the battle.

Hideyoshi rewarded Narinaga for his allegiance and merit in battle by making him lord of Mukaiyama Castle (Mukaiyama-jō, 向山城) in Gocho-gun, Bingo Province (today Mitsugi District, Hiroshima) and Matsuoka Castle (Matsuoka-jō, 松岡城) in Kōzan-cho, Sera-gun, Bingo Province.

In 1584 Narinaga donated a statue depicting a seated Mōri Motonari to Chōan Temple (Chōan-ji) at Iwami Ginzan Silver Mine.

In 1588 it is recorded that Hayashi Tosa-no-kami is promoted to the position where he receives direct orders from Hideyoshi on strategies in Kyūshū.

The reason Hideyoshi chose Narinaga for this was because he held extensive knowledge of Kyūshū where his ancestors from the Kikuchi clan had ruled.

The same month, Emperor Go-Yōzei visited Toyotomi Hideyoshi's mansion and the Sword hunt Edict was declared.

[15] In April and December 1592 Narinaga was sent as a diplomatic envoy between Toyotomi Hideyoshi and the Mōri clan along with Ankokuji Ekei (安國寺惠瓊).

There is a letter held at the Hiroshima Museum addressed to Mōri Terumoto from Toyotomi Hideyoshi and in it he expresses worry for his "old friend" Hayashi Hizen-no-kami who was old and at war.

His son, Motoyoshi, received an annual stipend of 2,290 koku which was twice as much as the Hayashi clan had before they left to the Chōshū Domain.

In September, 1597 Narinaga who was residing at Aka Castle rebuilt Hijiri Shrine (Hijiri-jinja, 聖神社) which had burned down.