Born 1854, last lord of Kakegawa Domain, descended from Ota Dokan. Inherited the domain at age eight in 1862. Ordered to defend Sunpu Castle during the 1868 Boshin War, then submitted to the new government; his domain was relocated to Kazusa's Musha and Yamabe Districts that year. In 1869, age fifteen, he set up a provisional office at Kannonkyo-ji and began governing as Shibayama Domain, then ordered construction of Matsuo Castle, named for his former seat Kakegawa Castle's alternate name. The residence was completed in 1870 and the domain renamed Matsuo in January 1871, but the castle town remained unfinished when the han was abolished that July. He is said to have established a domain school, hospital, and trade office during his tenure. After moving to Tokyo he supported former retainers and helped found Keio University, dying in 1913.

Local Sammu City records describe a precocious figure who became domain lord at eight and navigated the Bakumatsu turmoil, remaining devoted to former retainers and private education even after his domain vanished.

Though Matsuo Castle was never completed, the place name "Matsuo" survives as Sammu City's Matsuo district, and features like Kikyo-oka still recall the Ota family's crest.