The son of an artisan, he studied law at Toulouse and became a solicitor's clerk in Paris. Cladel made a reputation in a limited circle by his first book, Les Martyrs ridicules (1862), a novel for which Charles Baudelaire, whose literary disciple Cladel was, wrote a preface. He then returned to his native district of Quercy, where he produced a series of pictures of peasant life in Eral le dompteur (1865),Le Nomm Qouael (1868) and other volumes, similar to the works of Émile Pouvillon. Returning to Paris he published the two novels which are generally acknowledged as his best work, Le Bouscassie (1869) and La Fete votive de Saint Bartholome Porte-Glaive (1872). Une Maudite (1876) was judged dangerous to the public morals and cost its author a month's imprisonment. Other works by Cladel are Les Va-nu-pieds (1873), a volume of short stories; N'a-qu'un-oeil (1882), Urbains et ruraux (1884), Gueux de marque (1887), and the posthumous Juive errante (1897). He died at Sèvres on July 21, 1892.
- La Vie de Léon Cladel (Paris, 1905), by his daughter Judith Cladel, containing also an article on Cladel by Edmond Picard, a complete list of his works, and of the critical articles on his work.
- New General Catalog of Old Books and Authors
- The Symbolist Movement in Literature (1919), Arthur Symons
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Cladel, Léon". Encyclopædia Britannica (11th ed.). Cambridge University Press.