Kunikida grew up in southern Japan but went to Tokyo to enter Tokyo Senmon Gakkō (later Waseda University), where he adopted Christianity in 1889. He had already started to read the works of Ivan Turgenev, Thomas Carlyle, and Ralph Waldo Emerson when he went in 1893 to teach school in Saeki, on the southern Japanese island of Kyushu. That year, reinforced by his reading of William Wordsworth's poetry, was crucial in the development of his passionate devotion to nature. He returned to Tokyo, where he became a war correspondent for the newspaper of the influential critic and historian Tokutomi Sohō during the Sino-Japanese War (1894–95). His dispatches were collected and entitled Aitei tsūshin (“Letters to My Dear Brother”). Azamukazaru no ki (“Diary Without Deceit”) covered the personally tormented years of 1893–97, during which he married and was deserted by his first wife, who later served as the model for the heroine of the novel Aru onna (1919; A Certain Woman) by Arishima Takeo.

Kunikida is identified by the Japanese with their naturalist movement in literature, but his poetic stories of tragedies in the lives of downtrodden common people are more romantic than harshly realistic. His love of nature can be seen in Musashino (1898; “The Musashi Plain”), his search for idealism in Gyūniku to bareisho (1901; Meat and Potatoes), and his poignant feeling for the fate of wretched men in Gen oji (1897; Old Gen) and Haru no tori (1904; Spring Birds).