was a Japanese daimyo

Daimyo

is a generic term referring to the powerful territorial lords in pre-modern Japan who ruled most of the country from their vast, hereditary land holdings...

 of the Muromachi

Muromachi period

The is a division of Japanese history running from approximately 1336 to 1573. The period marks the governance of the Muromachi or Ashikaga shogunate, which was officially established in 1338 by the first Muromachi shogun, Ashikaga Takauji, two years after the brief Kemmu restoration of imperial...

 and Sengoku

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

 periods, and the head of the Hosokawa clan

Hosokawa clan

The ' was a Japanese samurai clan, descended from Emperor Seiwa and a branch of the Minamoto clan, by the Ashikaga clan. It produced many prominent officials in the Ashikaga shogunate's administration. In the Edo period, the Hosokawa clan was one of the largest landholding daimyo families in Japan...

. Harumoto's childhood name was Sōmei-maru (聡明丸). He was born to Hosokawa Sumimoto

Hosokawa Sumimoto

was a samurai commander in the Muromachi period during the 16th century of Japan.Sumimoto was one of the few sons of Hosokawa Yoshiharu and an adopted son of Hosokawa Masamoto, who was the Kanrei of the Ashikaga shogunate...

, another renowned samurai of the Muromachi era.

Harumoto succeeded to a house at the age of seven, after his father's death in 1520. While still a minor, he was supported by his caretaker Miyoshi Motonaga.

In 1531, Harumoto defeated Hosokawa Takakuni

Hosokawa Takakuni

Hosokawa Takakuni was the most powerful military commander in the Muromachi period under Ashikaga Yoshiharu, the twelfth shogun. His father was Hosokawa Masaharu, who was the branch of the Hosokawa clan....

, and regained the power. In addition, he feared Motonaga who had got credit and killed him next year.

After that, Harumoto ruled the whole area of Kinai

Kansai

The or the lies in the southern-central region of Japan's main island Honshū. The region includes the prefectures of Mie, Nara, Wakayama, Kyoto, Osaka, Hyōgo, and Shiga. Depending on who makes the distinction, Fukui, Tokushima and even Tottori Prefecture are also included...

 (Yamashiro Province

Yamashiro Province

was a province of Japan, located in Kinai. It overlaps the southern part of modern Kyoto Prefecture on Honshū. Aliases include , the rare , and . It is classified as an upper province in the Engishiki....

, Yamato Province

Yamato Province

was a province of Japan, located in Kinai, corresponding to present-day Nara Prefecture in Honshū. It was also called . At first, the name was written with one different character , and for about ten years after 737, this was revised to use more desirable characters . The final revision was made in...

, Kawachi Province

Kawachi Province

was a province of Japan in the eastern part of modern Osaka Prefecture. It originally held the southwestern area that was split off into Izumi Province...

, Izumi Province

Izumi Province

was a province of Japan. It is also referred to as . It lay in Kinai, and its area today composes the south-western part of Osaka Prefecture . The Ōshōji in Sakai was the border with Settsu Province, until the beginning of the Meiji period, when the boundary was changed to be at the Yamato River...

 and Settsu Province

Settsu Province

was a province of Japan, which today comprises the eastern part of Hyōgo Prefecture and the northern part of Osaka Prefecture. It was also referred to as or .Osaka and Osaka Castle were the main center of the province.-History:...

)
and took hold of the Ashikaga shogunate

Ashikaga shogunate

The , also known as the , was a Japanese feudal military regime, ruled by the shoguns of the Ashikaga clan.This period is also known as the Muromachi period and gets its name from Muromachi Street of Kyoto where the third shogun Ashikaga Yoshimitsu established his residence...

 as the Kanrei

Kanrei

or, more rarely, kanryō, was a high political post in feudal Japan; it is usually translated as Shogun's Deputy. After 1349, there were actually two Kanrei, the Kyoto Kanrei and the Kantō Kanrei....

.

In 1543, Hosokawa Ujitsuna

Hosokawa Ujitsuna

was a Japanese military commander and Deputy Shogun of the Hosokawa clan in the end of the Muromachi period and Sengoku period of the 16th century. He was the foster son of Hosokawa Takakuni....

 who was the foster son of Takakuni, raised his armies, and in 1549, Miyoshi Nagayoshi who was a dominant retainer and the first son of Motonaga betrayed Motoharu and took side with Ujitsuna.
Because of that, Harumoto was defeated.
Harumoto, Ashikaga Yoshiteru

Ashikaga Yoshiteru

, also known as Yoshifushi or Yoshifuji, was the 13th shogun of the Ashikaga shogunate who reigned from 1546 to 1565 during the late Muromachi period of Japan. He was the eldest son of the 12th shogun, Ashikaga Yoshiharu; and his mother was a daughter of Konoe Taneie...

 who was the 13th shogun

Shogun

A was one of the hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents , were the de facto rulers of Japan though they were nominally appointed by the emperor...

 and Ashikaga Yoshiharu

Ashikaga Yoshiharu

was the 12th shogun of the Ashikaga shogunate who held the reins of supreme power from 1521 through 1546 during the late Muromachi period of Japan...

 who was the father of Yoshiteru were purged to Ōmi Province

Omi Province

is an old province of Japan, which today comprises Shiga Prefecture. It was one of the provinces that made up the Tōsandō circuit. It is nicknamed as .Lake Biwa, Japan's largest lake, is located at the center of the province...

.

After that, Harumoto and Yoshiteru had battled with Nagayoshi for the power of the Ashikaga shogunate. However, Harumoto was beaten, and he retired after he reconciled himself with Nagayoshi in 1561. He died from a disease in 1563. The head family of the Hosokawa clan broke down as a result of his death.