While still a student at Nagano Normal School (now Shinshu University), he taught himself the basics of traditional Japanese poetry by studying the ancient Japanese literature classics such as the Man'yōshū and Kokinshū.
On graduation from university with a teaching certificate, he was hired by the local Matsumoto Higher Girls School.
His literary interests became a hobby, and he established a waka verse coterie, called Kono-hana Kai, with friends and students. This club resulted in the waka anthologies Tsuyukusa ("Dew Flower") in 1903 and Sanjo Kojo ("On Mountain, On Lake") in 1906 brought Ōta wide recognition, although he was only a co-author.
In 1909, Ota moved to Tokyo and was hired by the Nippon Dental University as a professor of ethics. In 1915, Ota began the tanka literary magazine, Choon to publicize his research, and gradually moved from creating his own verse to writing about the theory of tanka and his researches of the Japanese classics.
He married former student and fellow poet Shiga Mitsuko in 1910 and the two continued their creative activities while earning their living as teachers.