He was deeply influenced by Symbolism, especially in his earlier works. In 1930 he received the Pulitzer Prize for Poetry for his Selected Poems.
He wrote the widely anthologised short story "Silent Snow, Secret Snow" (1934); his collections of verse include Earth Triumphant (1914), The Charnel Rose (1918), and And In the Hanging Gardens (1933). His poem "Music I Heard" has been set to music by a number of composers, including Leonard Bernstein and Henry Cowell.
Aiken's tomb, located in Bonaventure Cemetery on the banks of the Savannah River, was made famous after its mention in Midnight in the Garden of Good and Evil, the bestselling book by John Berendt. According to local legend, Aiken wished to have his tombstone fashioned in the shape of a bench as an invitation to visitors to stop and enjoy a martini at his grave. Its inscriptions read "Give my love to the world," and "Cosmos Mariner—Destination Unknown."
He is the father of English writer Joan Aiken.