Lifespan: Bunmei 5 (1473) to 4/21 of Eishō 15 (1518)
Title: Assistant Vice-Minister of Civil Affairs
Lord: Ashikaga Yoshizumi → Ashikaga Yoshitane
Father: Uesugi Tomomasa
Adoptive Father: Uesugi Sadamasa
Siblings: Udagawa Chikasada, Tomomasa, Tomoyoshi, sister (formal wife of Uesugi Norifusa), Norikatsu (?)
Adopted Siblings: Sister (wife of Ōishi Akishige)
Children: Daughter (formal wife of Nagano Narimasa), Fujiōmaru
Adopted Children: Tomooki (natural son of Uesugi Tomonori)
Uesugi Tomoyoshi served as a bushō during the latter part of the Muromachi period and the Sengoku period. Tomoyoshi was the head of the Ōgigayatsu-Uesugi family.
Tomoyoshi was born as the son of Uesugi Tomomasa. He was adopted by his uncle, Uesugi Sadamasa. Tomoyoshi had an interest in studying texts so was frequently warned by his adoptive father to apply himself to the military arts.
In 1494, Sadamasa was killed in battle against Uesugi Akisada, the head of the Yamauchi-Uesugi and deputy shōgun of the Kantō. Tomoyoshi succeeded him as head of the clan, entering Kawagoe Castle in Musashi Province. Tomoyoshi pledged to avenge the death of Sadamasa, but, prior to his death in battle, Sadamasa believed slander from his retainers and purged Ōta Dōkan, alienating numerous retainers so that the Ōgigayatsu-Uesugi family fell into decline.
In the midst of these circumstances, Tomoyoshi requested support from Imagawa Ujichika, the military governor of Suruga Province, to overthrow Akisada. Ujichika responded by sending a senior retainer, Ise Sōzui (Hōjō Sōun), who had pacified Izu Province to have him assist Tomoyoshi. At this time, however, an event arose by which Sōzui captured Odawara Castle from Ōmori Fujiyori, a retainer of the Ōgigayatsu-Uesugi family. Owing to the importance of the relationship with the Imagawa clan, Tomoyoshi implicitly recognized the occupation of Odawara Castle by Sōzui. There is a theory that, with respect to the capture of Odawara Castle, Fujiyori had already been colluding with the Yamauchi-Uesugi and Sōzui captured the castle with the consent of Tomoyoshi.
In 1504, with the support of Imagawa Ujichika and Ise Sōzui, Tomoyoshi achieved a major victory against Akisada in Tachikawa-no-hara in Musashi at the Battle of Tachikawa-no-hara. Nevertheless, wielding greater power, Akisada soon counterattacked and Kawagoe Castle was surrounded by the Yamauchi-Uesugi army. Tomoyoshi surrendered and vacated the castle. Tomoyoshi adopted his nephew, Uesugi Tomooki (the son of Tomoyoshi’s older brother, Uesugi Tomomasa), transferred headship of the clan to Tomooki, and retired to Edo Castle. Senior retainers in the Ōgigayatsu-Uesugi family opposed this decision, while Akisada could not further coerce them so Tomoyoshi continued to serve as the head of the Ōgigayatsu-Uesugi family. Meanwhile, notwithstanding these circumstances, Ise Sōzui used the request from the Ōgigayatsu-Uesugi for military cooperation as justification to advance into Sagami Province, encroaching on territory governed by the Ōgigayatsu-Uesugi family.
In 1510, Akisada was killed in Echigo Province by Nagao Tamekage, the deputy military governor of Echigo. After it was discovered that Ise Sōzui encouraged Ueda Masamori, a senior retainer of the Ōgigayatsu-Uesugi, to leave the clan, Tomoyoshi and Tomooki reconciled with Uesugi Norifusa who had succeeded to the headship of the Yamauchi-Uesugi and commenced battle against Sōzui. Soon thereafter, succession struggles arose in the Yamauchi-Uesgui family and the family of the Koga kubō. Tomoyoshi urgently endeavored to mediate these disputes, but his efforts failed. In 1518, the last base of the Ōgigayatsu-Uesugi in Sagami was attacked and eliminated by Miura Yoshiatsu of the Miura District, an arch-rival of Sōzui, marking a definitive juncture in the decline of the Ōgigayatsu-Uesugi. Tomoyoshi died later that same year.
Tomoyoshi cherished a son born later in his life named Fujiōmaru. Tomoyoshi considered removing Tomooki to have Fujiōmaru become his successor. After Tomoyoshi’s demise, however, the Ōgigayatsu-Uesugi family was enveloped in internal conflict, further accelerating its decline.