After his family suffered financial reverses, Robinson cut short his attendance at Harvard University (1891–93) and returned to Gardiner to stay with his family, whose fortunes were disintegrating. The lives of both his brothers ended in failure and early death, and Robinson's poetry is much concerned with personal defeat and the tragic complexities of life. Robinson himself endured years of poverty and obscurity before his poetry began to attract notice.

His first book, The Torrent and the Night Before, was privately printed at his own expense. His subsequent collections, The Children of the Night (1897) and The Town Down the River (1910), fared little better, but the publication of The Man Against the Sky (1916) brought him critical acclaim. In these early works his best poetic form was the dramatic lyric, as exemplified in the title poem of The Man Against the Sky, which affirms life's meaning despite its profoundly dark side. During these years Robinson perfected the poetic form for which he became so well known: a structure based firmly on stanzas, skillful rhyming patterns, and a precise and natural diction, combined with a dramatic examination of the human condition. Among the best poems of this period are “Richard Cory,” “Miniver Cheevy,” “For a Dead Lady,” “Flammonde,” and “Eros Turannos.” Robinson broke with the tradition of late Romanticism and introduced the preoccupations and plain style of naturalism into American poetry. His work attracted the attention of President Theodore Roosevelt, who gave him a sinecure at the U.S. Customs House in New York (held from 1905 to 1909).

In the second phase of his career, Robinson wrote longer narrative poems that share the concern of his dramatic lyrics with psychological portraiture. Merlin (1917), the first of three long blank-verse narrative poems based on the King Arthur legends, was followed by Lancelot (1920) and Tristram (1927). Robinson's Collected Poems appeared in 1921. The Man Who Died Twice (1924) and Amaranth (1934) are perhaps the most often acclaimed of his later narrative poems, though in general these works suffer in comparison to the early dramatic lyrics. Robinson's later short poems include “Mr. Flood's Party,” “Many Are Called,” and “The Sheaves.”