Ensor was criticized on occasion as "the benighted and supremely naïve artist" and called himself a "sensible writer, painter [...], composer of tender Gammes d'Amour". In 1884, the newspaper L'Art moderne publishes "Trois semaines à l'Académie" with the subtitle of "Monologue à tiroirs" (a theatre piece with intrigues). It is the first text that Ensor published, but the publication is not signed. Later, however, he used the anagram Senor from time to time. From 1896, he published in Le coq rouge and in La ligue artistique; libre tribune d'art et de littérature (newspapers that were published in Brussels) news reports about the worldly life in Ostend, art criticism pieces (Au musée moderne), satirical pieces on the laureate of the Prix de Rome (Jean Delville), about the brothers Joseph, Arthur and Alfred Stevens, the death of the antiquated Flemish artistic tradition, or satirical reviews of exhibitions. In addition, in the Ostend daily and weekly papers he published similar satirical art criticism accounts.
A considerable portion of Ensor's writings consists of addresses to the introduction of important manifestations. For example, he wrote orations for the organisation of large exhibitions of his work in the Brussels Galérie Giroux in 1919, or in 1921 for the Kunst van Heden/l'Art Contemporain in Antwerp, for a banquet in honour of the La Flandre Littéraire in 1923, for the retrospective exhibitions in the Palace of Fine Arts/Palais des Beaux-Arts in Brussels in 1929 and in the Jeu de Paume in Paris in 1932, for the installment of his portrait bust in Ostend in 1930, for the performance of the ballet La Gamme d'Amour in Liège in 1927 and in Ostend in 1932, for the dealings of the decorations of the French Légion d'Honneur in 1933, for the celebration of his honorary title "Prince of Painters" at the Bal des Artistes in 1934 and for the festivities of his 75th birthday in Ostend. The speeches apparently were popular as Ensor was requested often. Subsequently, he wrote laudatory speeches for Auguste Oleffe (1920), Grégoire Le Roy (1920) Isidoor De Rudder (1920), Jules Destrée (1921), Claude Bernières (1923), Pieter Bruegel (1924), Henri Cassiers (1925), Amedée Lynen (1924), Karel Van de Woestijne (1925), Carol Deutsch (1929) and for other exhibitions that Blance Hertoghe organised in the 1930's in the Ostend Galerie Studio.
The first publication of a large selection of Ensor's writings was published in 1921 by Sélection. Les écrits de James Ensor, avec 36 réproductions d'après les dessins originaux du peintre bundled together 24 texts. La Flandre Littéraire. Revue mensuelle d'art et de littérature that appeared from 1922 to 1927 published loose texts by Ensor every now and then, and in 1926 ensured for a new collection of recent texts. The Antwerp exhibition association, Kunst van Heden/L'Art contemporain, published then in 1934 a third collection with recent writings. The plan of André De Ridder, art critic and economist, to make an edition of all writings, was carried out just after WWII. The 63 texts that were published in 1921, 1926 and 1934 were brought together anew in Les écrits de James Ensor, published in Brussels by Editions Lumière in 1944. After Ensor's death, one Dutch edition and more French editions were published. None of these is exhaustive. Dozens of manuscripts are preserved in public and private collections.
In Le Mal du Pays, Autobiographie de la Belgique (Paris 2003), the French-language writer Patrick Rogiers called Ensor, "the greatest writer, creator and illustrious one of the Belgian language of the 20th Century". Ensor loved humorous litanies, an archaic vocabulary and neologisms. At times, his language use duly put to the test the patience of non-francophone readers. Ensor also spoke Dutch, the language of his mother and her family. He did not have a strong command of Dutch, but did still produce a few texts.