Valéry is best known as a poet, and he is sometimes considered to be the last of the French symbolists. However, he published fewer than a hundred poems, and none of them drew much attention. On the night of 4 October 1892, during a heavy storm, Paul Valéry underwent an existential crisis, an event that made a huge impact on his writing career. Eventually, around 1898, he quit writing altogether, publishing not a word for nearly twenty years. This hiatus was in part due to the death of his mentor, Stéphane Mallarmé. When, in 1917, he finally broke his 'great silence' with the publication of La Jeune Parque; he was forty-six years of age.

One of three epigraphs in Cormac McCarthy's novel Blood Meridian is from Valéry's Writing at the Yalu River (1895):

In 1900, he married Jeannie Gobillard, a friend of Stéphane Mallarmé's family, who was also a niece of the Painter Berthe Morisot. The wedding was a double ceremony in which the bride's cousin, Morisot's daughter, Julie Manet married the Painter, Ernest Rouart. Valéry and Gobillard had three children: Claude, Agathe and François.

Valéry served as a juror with Florence Meyer Blumenthal in awarding the Prix Blumenthal, a grant given between 1919 and 1954 to young French Painters, Sculptors, decorators, engravers, Writers, and Musicians.

Before la Jeune Parque, Valéry's only publications of note were dialogues, articles, some poems, and a study of Leonardo da Vinci. In 1920 and 1922, he published two slim collections of verses. The first, Album des vers anciens (Album of old verses), was a revision of early but beautifully wrought smaller poems, some of which had been published individually before 1900. The second, Charmes (from the Latin carmina, meaning "songs" and also "incantations"), further confirmed his reputation as a major French poet. The collection includes le Cimetière marin, and many smaller poems with diverse structures. 'Le Cimetière marin' is mentioned or indirectly implied or referred to in at least four of Iris Murdoch's novels, The Unicorn, The Time of the Angels, The Nice and the Good and The Sea, The Sea.

After his election to the Académie française in 1925, Valéry became a tireless public speaker and intellectual figure in French society, touring Europe and giving lectures on cultural and social issues as well as assuming a number of official positions eagerly offered to him by an admiring French nation. He represented France on cultural matters at the League of Nations, and he served on several of its committees (the sub-committee on Arts and Letters of the Committee on intellectual cooperation) . The Outlook for Intelligence (1989) contains English translations of a dozen essays resulting from these activities.

In 1931, he founded the Collège International de Cannes, a private institution teaching French language and civilization. The Collège is still operating today, offering professional courses for native speakers (for educational certification, law and business) as well as courses for foreign students.

He gave the keynote address at the 1932 German national celebration of the 100th anniversary of the death of Johann Wolfgang Goethe. This was a fitting choice, as Valéry shared Goethe's fascination with science (specifically, biology and optics).

In addition to his activities as a member of the Académie française, he was also a member of the Academy of Sciences of Lisbon, and of the Front national des Ecrivains. In 1937, he was appointed chief executive of what later became the University of Nice. He was the inaugural holder of the Chair of Poetics at the Collège de France.

Valéry died in Paris in 1945. He is buried in the cemetery of his native town, Sète, the same cemetery celebrated in his famous poem, Le Cimetière marin.

Valéry's technique is quite orthodox in its essentials. His verse rhymes and scans in conventional ways, and it has much in Common with the work of Mallarmé. His poem, Palme, inspired James Merrill's celebrated 1974 poem Lost in Translation, and his cerebral lyricism also influenced the American poet, Edgar Bowers.

The subjects of his Cahiers entries often were, surprisingly, reflections on science and mathematics. In fact, arcane topics in these domains appear to have commanded far more of his considered attention than his celebrated poetry. The Cahiers also contain the first drafts of many aphorisms he later included in his books. To date, the Cahiers have been published in their entirety only as photostatic reproductions, and only since 1980 have they begun to receive scholarly scrutiny. The Cahiers have been translated into English in five volumes published by Peter Lang with the title Cahiers/Notebooks.

Oscar-winning Japanese Director Hayao Miyazaki's 2013 film The Wind Rises and the Japanese novel of the same name (on which the film was partially based) take their title from Valéry's verse "Le vent se lève... il faut tenter de vivre !" ("The wind rises… We must try to live!") in the poem "Le Cimetière marin" (The Graveyard By The Sea). The same quote is used in the closing sentences of Anthony Burgess's 1962 novel The Wanting Seed.