Lifespan: Eiroku 10 (1567) to 3/23 of Keichō 8 (1603)
Title: Junior Fifth Rank (Lower), Governor of Tōtōmi
Lord: Toyotomi Hideyoshi → Tokugawa Ieyasu
Domain: Tōki – hatamoto
Father: Koide Hidemasa
Mother: Eishōin (the younger sister of Ōmandokoro, the mother of Toyotomi Hideyoshi)
Siblings: Yoshimasa, Hideie, Nichijū, Mitsutada, Shigekata, Hidekiyo
Adopted Children: Mitsutada, Shigekata
Koide Hideie served as a bushō during the Azuchi-Momoyama period and as a hatamoto during the early Edo period. He was the first head of the branch of the Koide family in the Tōki domain in Izumi Province. He had the common name of Magojūrō.
In 1567, Hideie was born as the second son of Koide Hidemasa. His mother was Eishōin, the younger sister of Ōmandokoro, the mother of Toyotomi Hideyoshi. Hideie was therefore a younger cousin of Hideyoshi. Koide Yoshimasa was his older brother of the same mother and Koide Mitsutada was his younger brother of a different mother. Similar to Yoshimasa, from an early age, Hideie served as an umamawari, or member of the cavalry, for Hideyoshi.
Around 1591, he was awarded a fief of 1,000 koku in the Ōtori District of Izumi Province.
In 1592, during the Bunroku Campaign on the Korean Peninsula, he was stationed at Nagaoya Castle in the Matsura District of Hizen Province and his name appears as a member of the Sannomaru guards and cavalry units. During the Bunroku era (1593 to 1596), Hidie was invested with the titles of Junior Fifth Rank (Lower) and Governor of Tōtōmi.
In the early summer of 1600, when Tokugawa Ieyasu headed out to conquer Uesugi Kagekatsu in the Conquest of Aizu, Hideie joined on behalf of his father, leading 300 troops. En route to Aizu, Hideie learned while in Oyama in Shimotsuke Province that Ishida Mitsunari had launched a revolt in Ōsaka and that his father and older brother had joined the Western Army led by Mitsunari. Nevertheless, Hideie continued to follow Ieyasu as a member of the Eastern Army. At a war council known as the Oyama Deliberation, Ieyasu made a crucial decision to forego the conflict with Kagekatsu and instead turned back his forces westward to confront Mitsunari. In the ninth month, Hideie served for the Tokugawa army in the Battle of Sekigahara.
After returning to Izumi and requisitioning the former base of his father at Kishiwada Castle, over 200 naval vessels with forces led by Chōsokabe Morichika of the Western Army made landfall in Izumi from Shikoku so he fought to repel them. Ieyasu praised Hideie’s valor, increasing his fief by 1,000 koku in the Nishigori District of Kawachi Province. As a result, Hideie acquired a fief of 2,000 koku in total and obtained recognition of the rights of his father and older brother (who had joined the Western Army) to their territories.
In 1603, Hideie died of illness in Ōsaka at the age of thirty-seven. He received the posthumous Buddhist name of Ryōshun. Ieyasu regretted his death and, rather than remove the family from their position, permitted the adoption of his younger brother, Mitsutada to inherit the headship of the clan.
The next year, after the death of Hidemasa, Ieyasu ordered Yoshimasa to allocate a fief of 10,000 koku to Mitsutada as the successor to Hideie to establish the Tōki domain in the Ōtori District of Izumi.