Tokugawa Ienari
Ōta Sukenobu was the second son of Ōta Sukeyoshi, the previous "daimyō" of Kakegawa Domain, by a concubine. As his elder brother Ōta Suketake died in 1785, he inherited the leadership of the Ōta clan and position of "daimyō" of Kakegawa Domain on the death of his father in 1805. The following year, he was appointed as "sōshaban" at Edo Castle in the service of "Shōgun" Tokugawa Ienari.