Born in Milford Haven, Wales, to Cornish parents, Symons was educated privately, spending much of his time in France and Italy.

[citation needed] In 1892, The Minister's Call, Symons's first play, was produced by the Independent Theatre Society – a private club – to avoid censorship by the Lord Chamberlain's Office.

[3] Symons conducted a long-lasting relationship with a secret lover who has never been identified, commemorated in his book Amoris Victima; in 1901 (19 June) he married Rhoda Bowser (1874–1936), an aspiring actress and oldest daughter of a Newcastle-upon-Tyne shipping magnate.

[4] Symons's 1897 book Studies in Two Literatures was one of his earliest works as a “serious critic” and established lyricism, mysticism, profundity, modernity, and sincerity as the various traits he would consider in his critiques.

He translated from the Italian of Gabriele D'Annunzio The Dead City (1900) and The Child of Pleasure (1898), and from the French of Émile Verhaeren The Dawn (1898).

To The Poems of Ernest Dowson (1905) he prefixed an essay on the deceased poet, who was a kind of English Verlaine and had many attractions for Symons.

After wandering lost through the countryside for two days, suffering fatigue and symptoms of madness, he was found and arrested by two Italian soldiers and held in prison in Ferrara.

Symons would later go on to publish his own book titled Studies on Modern Painters in 1925 using many of the articles he wrote for Weekly Critical Review and Outlook.

[7] In 1918, Vanity Fair magazine published Symons's Baudelarian essay, "The Gateway to an Artificial Paradise: The Effects of Hashish and Opium Compared."