Daijō Kiyomoto served as a bushō during the Azuchi-Momoyama period. He was the lord of Fuchū Castle in Hitachi Province and the last head of the Daijō clan.
In 1573, Kiyomoto was born as the son of Daijō Sadakuni.
After the death of his father, Kiyomoto inherited the headship of the clan at the age of five. Owing to his youth, he could not govern so his uncle (Sadakuni’s younger brother) named Takehara Yoshikuni served as his guardian. At the time, the Daijō were members of an association of clans led by Satake Yoshishige. This group engaged in a struggle for power against the Gohōjō faction including Oda Ujiharu. After maturing, Kiyomoto attempted to mediate a settlement between Utsunomiya Kunitsuna and Nasu Sukeharu who were members of the same association but he also competed for power against Edo Shigemichi who was a fellow member of the same group.
In the eighth month of 1585, Kiyomoto and Shigemichi engaged in battle for control of the Sonobe River Basin. In this event, Kiyomoto received support from the Makabe clan while Shigemichi allied with the Shishido. The Satake clan attempted to forge a settlement but failed so the situation became even more serious. As a result, the Yūki clan, together with the Satake, joined the mediation for a settlement and, in the eleventh month of 1586, the two sides finally reconciled. This event is known as the First Battle of Fuchū.
Nevertheless, from the first month of 1588, the battle between the two sides reignited. The Satake clan attempted to mediate again, but, after Satake Yoshishige and Satake Yoshinobu (father and son) deployed forces to assist the Edo clan, Kiyomoto was determined to fight and sought support from the Hōjō against whom he was previously opposed. Meanwhile, the Satake joined forces with Edo Shigemichi, Kashima Kiyohide, and Kamata Michimoto and, from Ogawa Castle, approached Fuchū Castle, defeating the forces of Kiyomoto along with reinforcements from Makabe Ujimoto. In the fifth month, Kiyomoto settled on terms that were a de facto surrender. This is known as the Second Battle of Fuchū.
As members of the Satake clan, the Edo were subordinate to the Satake. In contrast, the Daijō, similar to the Utsunomiya and Nasu clans, stood in the position of allies of the Satake. The Satake were not necessarily seeking to subjugate or decimate the Daijō, rather, it appears the objective was to support the Edo as one of the measures to bring security to those in the Satake who were shaken by the southward advance of Date Masamune.
Acting in the interests of the Makabe clan, Makabe Ujimoto assisted Kiyomoto and fought against Satake Yoshishige and Satake Yoshinobu while, at the same time, maintained communications with Satake Yoshinori in an effort to achieve peace.
Thereafter, the conflict between the Edo and Daijō clans does not appear to have been resolved. In 1590, during the Conquest of Odawara, Kiyomoto sent a letter to Hideyoshi to request an apology from Satake Yoshinobu who, upon orders of Hideyoshi, had deployed for the campaign. In fact, Shigemichi took similar actions. The Daijō and Edo clans had the intention of deploying for the campaign, but both feared that, while absent, their bases would be attacked by the other side so they could not deploy and desired Yoshinobu, as their ally, to request Hideyoshi to intervene. Yoshinobu, however, viewed the situation as an opportunity to unify Hitachi, so he disregarded the request from the Edo and Daijō clans to intervene and, on 8/1, obtained recognition of his rights from Hideyoshi to all of the territory in Hitachi amounting to 540,000 koku. In the twelfth month, after toppling the base of the Edo clan at Mito Castle, the army of Satake Yoshishige continued to advance southward to capture Fuchū Castle. After losing his castle, Kiyomoto took his own life and the Daijō clan was extinguished.
Based on a letter discovered in 2016 from a retainer of Ishida MItsunari named Shima Kiyooki (Shima Sakon), Daijō Kiyomoto made a request to defer the tendering of hostages requested by the Toyotomi administration and Shima served as the lead negotiator for the Toyotomi. There is a strong likelihood that the failure of these negotiations caused the Toyotomi administration to permit the elimination of the Daijō by the Satake.