Tadataka was born in Kamiwada, Mikawa Province, the son of Tokugawa retainer Ōkubo Tadakazu.

He joined Tadayo at age 17 for his first campaign, during the subjugation of Tōtōmi Province.

Tadataka served with distinction at the Battle of Takatenjin Castle, taking the head of enemy general Okabe Motonobu.

After the Siege of Odawara, when Tokugawa Ieyasu moved to the Kantō Region, he granted Tadataka land assessed at 3,000 koku, and appointed him yari-bugyō (magistrate of spears) in the Tokugawa main battle camp.

Tadataka also served at Sekigahara and the Siege of Osaka; his service stretched over the careers of the first three Tokugawa shōguns.