Lifespan: Tenbun 23 (1554) to 11/24 of Tenshō 15 (1587)
Other Names: Ujitaka, Mutō Yoshioki, Maruoka-Hyōgo
Clan: Daihōji (descended from the Mutō clan of the Fujiwara lineage)
Father: Daihōji Yoshimasu
Siblings: Yoshiuji, Yoshioki
Adopted Children: Shōsenmaru (second son of Honjō Shigenaga)
Daihōji Yoshioki served as a daimyō during the Azuchi-Momoyama period. He was the eighteenth head of the Daihōji clan.
In 1554, Yoshioki was born as the second son of Daihōji Yoshimasu. Initially, he was based at Maruoka Castle in the Kushibiki District of Dewa Province.
In 1579, his older brother, Daihōji Yoshiuji, the seventeenth head of the Daihōji clan, received the title of Yakata from Oda Nobunaga with whom he maintained friendly relations and then transferred the role of bettō or steward of the sacred shrines on Mount Haguro in Dewa to Yoshioki. Thereafter, as a priest, and as deputy to his older brother, Yoshioki promoted Mount Haguro and the Daihōji family but, in 1583, owing to rebellion by a retainer named Tōzenji Yoshinaga, Yoshiuji took his own life. Yoshioki then entered Oura Castle and succeeded his brother as the head of the family.
Yoshioki did not have a son. Moreover, reflecting the importance placed on his relations in Echigo, he adopted the second son (Senshōmaru) of Honjō Shigenaga, an influential retainer of the Uesugi. Senshōmaru was later known as Daihōji Yoshikatsu. This enabled Yoshioki to garner the support of Shigenaga. Rather than serve the Mogami clan, Yoshioki desired to pursue a path toward independence, and it was a bold and difficult choice to depend, in the event necessary, upon the Honjō and Uesugi clans. In 1585, after Yoshioki assaulted Shimizu Castle which was aligned with the Mogami, the kokujin, or provincial landowners, in the shōen, or manor, who supported the Mogami joined together in a revolt. Viewing this as a good opportunity, Mogami Yoshiaki led his army, traveled the Rokujūrigoe Road and invaded the manor. Owing to an attack in Shibata, Shigenaga could not come to his aid so Yoshioki turned to Date Masamune, the powerful sengoku daimyō of Mutsu Province to enter into a settlement, but retainers of the Daihōji, Tōzenji Yoshinaga and his younger brother, Tōzenji Katsumasa, rebelled. Yoshioki surrounded Tōzenji Castle, but, following the arrival of reinforcements from Yoshiaki, the situation turned completely around. After a valiant battle at the end of a one-year siege, his base at Oura Castle was toppled and, in the end, Yoshioki took his own life.
His adopted son, Daihōji Yoshikatsu, fled back to his harsh natural father, Honjō Shigenaga, preserving a trace of the Daihōji clan.