A poet and official of the early Heian period. In 905, by command of Emperor Daigo, he compiled the "Kokinshu" (Collection of Ancient and Modern Poems) and wrote its kana preface. This kana preface, as the first work of literary and poetic theory written in the Japanese language, has epoch-making significance in the history of Japanese literature. The opening line — "Japanese poetry (yamato uta) takes the human heart as its seed and grows into the ten thousand leaves of words" — continues to define the aesthetics of Japanese literature more than a thousand years later. He is one of the Six Poetic Sages, and his poem "As for people, I cannot know their hearts; but in this old village, the blossoms still bloom with the scent of long ago" is included in the Hyakunin Isshu. He served as governor of Tosa Province from 930 to 935, and his account of the journey home written in the guise of a woman's diary, "The Tosa Diary," is significant as Japan's oldest diary literature.

A intellectually oriented poet with deep knowledge of literature and a rigorous aesthetic sense. He was also a pioneer of literary criticism, as shown in his standards for selecting the Six Poetic Sages in the Kokinshu compilation. In the Tosa Diary he achieved free emotional expression by adopting the mask of a woman.

The kana preface of the Kokinshu is the origin of Japanese literary theory. "The Tosa Diary" was a forerunner of Japanese essay and diary literature, exerting enormous influence on subsequent writers including Murasaki Shikibu and Sei Shonagon.