As a youth, Ōtsuki was employed as an advisor to Sendai Domain, and fought at the Battle of Toba–Fushimi in the Boshin War of the Meiji Restoration on the losing Tokugawa Bakufu side.

Around 1872, he joined in the editing of an English–Japanese dictionary for the Ministry of Education, and he later worked on textbooks and taught at schools in Miyagi Prefecture.

Although Ōtsuki paid for the original publication expenses for Genkai himself, it was soon republished and expanded in commercial editions that went through over a thousand printings.

Modeled in part on Western monolingual dictionaries, Genkai gave not only basic information about words—their representations in kana and kanji and their definitions in Japanese—but also pronunciations and etymologies and citations of their use.

Its successor, the four-volume Daigenkai, though published under Ōtsuki's name and based in part on his work, appeared some years after his death and was completed by other lexicographers.