Lifespan: Meiō 1 (1492) to 2/22 of Tenbun 17 (1548)
Other Names: Kamewakamaru (childhood)
Rank: sengoku daimyō
Title: Junior Fourth Rank (Upper), Lieutenant General of Imperial Guards of the Left Division, Master of the Eastern Capital Office
Clan: Ashikaga (Horigoe kubō family) → Oda
Father: Ashikaga Masatomo (?)
Adoptive Father: Oda Shigeharu (?)
Siblings: Ashikaga Chachamaru, Ashikaga Jundōji, Ashikaga Yoshizumi, Masaharu (?)
Children: Tomoharu, Ujiharu, Takaharu
Oda Masaharu served as a sengoku daimyō of Hitachi Province during the Sengoku period. He was the fourteenth head of the Oda clan and referred to as the ancestor who rejuvenated the family, raising them to the status of a sengoku daimyō while ushering in their peak period of prosperity.
In 1492, Masaharu was born as the son of Ashikaga Masatomo, the Horigoe kubō. His father, Masatomo, died in the prior year so Masaharu would have been born after his demise. Under another theory, Masaharu was the younger brother of Ashikaga Yoshizumi, the eleventh shōgun of the Muromachi bakufu. However, according to records of the Oda, he was the third son of Oda Shigeharu, the thirteenth head of the Oda clan. There is also a theory that he was the same individual as the son of Masatomo named Masauji or an illegitimate child of Masatomo.
In 1514, following the demise of Oda Shigeharu, Masaharu succeeded him as the fourteenth head of the Oda clan. Prior to Masaharu’s ascension, Shigeharu’s eldest son, Oda Harutaka, served as the thirteenth head of the clan for a brief period but was killed in a succession struggle by his younger brother, Oda Akiie, who was, in turn, ousted.
In the power-struggle in the Koga kubō, Masaharu joined Utsunomiya Shigetsuna, Utsunomiya Tadatsuna, Yūki Masatomo in support of Ashikaga Takamoto in opposition to sengoku daimyō and others who backed Ashikaga Masauji, including Satake Yoshikiyo, Oyama Shigenaga, Iwaki Tsunetaka, Iwaki Yoshitaka, and Yūki Akiyori.
After Takamoto defeated his father, Masauji, and became the next Koga kubō, Masaharu feared the rapid rise of the Gohōjō clan in southern Kantō. He then arranged for his younger sister to wed Satake Yoshiatsu with the aim of forging a political alliance with the Satake.
In 1531, at the Battle of Ishioka, Masaharu defeated the Edo clan. In 1537, he allied with the Tagaya clan to fight against Yūki Masakatsu, but lost. He continued to battle against enemy forces in multiple directions including against the Koga kubō (the Kantō branch of the ruling Ashikaga family), expanding the influence of the Oda clan. In 1545, at the Siege of Kawagoe Castle, Masaharu fought against Ashikaga Haruuji, but was defeated. In his latter years, the Oda clan began to decline.
On 2/22 of Tenbun 17 (1548), Masaharu died at the age of fifty-seven. He was succeeded by his eldest son, Oda Ujiharu.