Early inspired by a French governess who instilled in him a passion for French poetry, Moréas moved to Paris in 1879, becoming a familiar figure in the literary circles frequenting the cafés and in the literary pages of newspapers and reviews. He published two manifestos, one in XIXe Siècle (Aug. 11, 1885) and one in the literary supplement of Le Figaro (Sept. 18, 1886), that helped establish the name Symbolism for the movement that was growing out of and replacing Decadence. In 1886, with Gustave Kahn (Kahn, Gustave) and Paul Adam (Adam, Paul), he founded the periodical Le Symboliste.

Before Moréas immigrated to France, he published one volume of verse, Tourterelles et vipères (1878; “Turtledoves and Vipers”), in Greek and French. His first wholly French volumes, Les Syrtes (1884) and Les Cantilènes (1886), were firmly embedded in the Decadent and Symbolist aesthetics. In the preface to Le Pèlerin passioné (1891; “The Passionate Pilgrim”), however, Moréas began to forsake Symbolism; there he called for a return to the spirit of classicism. Moréas founded the école romane (“Roman school”) and, with his disciples Raymond de la Tailhède, Maurice du Plessys, Ernest Raynaud, and Charles Maurras (Maurras, Charles), reverted to classical forms and subject matter; free verse was abandoned and classical sources of inspiration were used. Énone au clair visage (1893) and Eriphyle (1894) are representative of Moréas' work during this period; along with other poems, they were later collected as Poèmes et sylves, 1886–1896 (1907; “Poems and Forests”). Moréas wrote a verse play, Iphigénie à Aulide (1903), which was closely inspired by Euripides and which met with considerable success when presented in the théâtre antique of Orange and subsequently on the stage of the Odéon in Paris. In Moréas' last work, Les Stances (1899–1920; “The Stanzas”), his intellectual development is chronicled with a vigorous yet melancholy classicism.