[1] Tadaaki was born in 1583, the fourth son of Okudaira Nobumasa, a senior Tokugawa retainer.

He assumed the adult name of Kiyomasa, which he changed to Tadaaki in 1599, after receiving the tada (忠) character from Tokugawa Hidetada's name.

[1] He was made daimyō of a domain within the provinces of Settsu and Kawachi worth 100,000 koku.

In his later years, Tadaaki assisted with the management of the fledgling Tokugawa Shogunate; he died at his estate in Edo in 1644.

His descendants had their holdings moved several times, and eventually became rulers of the Oshi Domain, where they remained until the Meiji Restoration.