Okubo Choan was born in 1545. He was the son of Shichiro Komparu, an actor of sarugaki, an earlier form of Noh drama.
Okubo Choan served the Takedas in Kai Provnce (Yamanashi Prefecture) as samurai. After the Takeda family's downfall, he lived in Sumpu (Shizuoka City) as a sarugaku actor, calling himself Okura-Taifu. Ieyasu Tokugawa made him Magistrate of Gold Mines. He then became a retamer of Tadachika Okubo, one of Ieyasu's vassals, and received the family name of Okubo from Tadachika. He enjoyed high confidence of Ieyasu and was made Lord of the Hachioji area west of Edo, with a fief of 30,000 koku. In 1604, he caused milestones to be erected on the Tokai, Tosan and Hokuriku highways. Introduced new devices in castle architecture and reformed the penal code prevalent in those days.
After his death, his correspondence with foreign countries and documentary evidence showing his connections with Christians were discovered and all members of his family were put to death.