Born as the son of Ouchi Yoshioki, heir to a powerful western Honshu clan. Raised amid the Ouchi courtly tastes in Yamaguchi, where Kyoto-style culture mixed with warrior politics.

As a child, he saw his father Yoshioki retreat from Kyoto after costly interventions in shogunal affairs. The experience highlighted how distant capital politics could drain resources from Suo and Nagato.

After Yoshioki’s death, he became Ouchi clan leader and inherited extensive holdings and trade networks. He relied on senior retainers, including Sue Harukata, to manage armies while he shaped policy and culture.

He expanded Yamaguchi as a "Little Kyoto," inviting poets, painters, and nobles displaced by unrest. The Ouchi capital became known for renga gatherings, elegant ceremonies, and a flourishing book culture.

He cultivated links with Zen institutions that supported diplomacy and literacy, drawing on monk-scholars for statecraft. These networks helped the Ouchi communicate with overseas partners and circulate new texts.

The Ouchi leveraged ports in the Inland Sea and northern Kyushu to profit from regional shipping and foreign commerce. Yoshitaka promoted regulated trade channels that connected his domain to continental goods and knowledge.

As Amago Haruhisa expanded from Izumo, Yoshitaka faced pressure to fight for influence in western Honshu. Strategic decisions increasingly depended on generals like Sue Harukata and other militarized branch families.

With Francis Xavier’s mission entering Japan, Yoshitaka became a notable daimyo interested in foreign visitors and learning. He allowed the Jesuits to operate in his territory, seeing potential diplomatic and commercial benefits.

He received Francis Xavier and offered protections that let the missionaries preach and travel. The meeting symbolized Yamaguchi’s openness to new ideas, even as many warriors viewed the faith with suspicion.

As matchlock guns spread after their introduction to Japan, Yoshitaka’s forces faced changing battlefield expectations. His administration sought to keep pace through procurement and port-based trade, though rivals adapted quickly.

Under pressure to secure prestige and territory, he authorized ambitious operations aimed at Amago strongholds. The campaigns strained finances and morale, sharpening disagreements between Yoshitaka’s courtly priorities and his generals’ demands.

Repeated military burdens and perceived favoritism toward cultured courtiers fueled resentment in the Ouchi ranks. Sue Harukata and other leaders increasingly positioned themselves as defenders of practical governance and martial discipline.

As factionalism deepened, Yoshitaka struggled to balance ritual legitimacy with wartime realities. Key administrative posts and castle commands shifted toward Sue Harukata’s network, leaving the daimyo isolated within his own capital.

Sue Harukata moved decisively against him, seizing Yamaguchi and forcing loyalists to flee. The coup, remembered as the Tainei-ji incident, shattered the Ouchi regime that had dominated western Honshu politics.

Fleeing the capital, he sought refuge but was pursued by Sue’s forces and cornered at Tainei-ji. He died there in 1551, marking the effective end of Ouchi Yoshitaka’s rule and the clan’s cultural golden age.