In Paris, under the influence of poets and writers, he developed his unique style: organic forms and flattened picture planes drawn with a sharp line. Generally thought of as a Surrealist because of his interest in automatism and the use of sexual symbols (for example, ovoids with wavy lines emanating from them), Miró's style was influenced in varying degrees by Surrealism and Dada, yet he rejected membership in any artistic movement in the interwar European years. André Breton described him as "the most Surrealist of us all." Miró confessed to creating one of his most famous works, Harlequin's Carnival, under similar circumstances:
"How did I think up my drawings and my ideas for painting? Well I'd come home to my Paris studio in Rue Blomet at night, I'd go to bed, and sometimes I hadn't any supper. I saw things, and I jotted them down in a notebook. I saw shapes on the ceiling..."
Miró's surrealist origins evolved out of "repression" much like all Spanish surrealist and magic realist work, especially because of his Catalan ethnicity, which was subject to special persecution by the Franco regime. Also, Joan Miró was well aware of Haitian Voodoo art and Cuban Santería religion through his travels before going into exile. This led to his signature style of art making.
Joan Miró was among the first artists to develop automatic drawing as a way to undo previous established techniques in painting, and thus, with André Masson, represented the beginning of Surrealism as an art movement.[by whom?] However, Miró chose not to become an official member of the Surrealists in order to be free to experiment with other artistic styles without compromising his position within the group. He pursued his own interests in the art world, ranging from automatic drawing and surrealism, to expressionism, Lyrical Abstraction, and Color Field painting. Four-dimensional painting was a theoretical type of painting Miró proposed in which painting would transcend its two-dimensionality and even the three-dimensionality of sculpture.
Miró's oft-quoted interest in the assassination of painting is derived from a dislike of bourgeois art, which he believed was used as a way to promote propaganda and cultural identity among the wealthy. Specifically, Miró responded to Cubism in this way, which by the time of his quote had become an established art form in France. He is quoted as saying "I will break their guitar," referring to Picasso's paintings, with the intent to attack the popularity and appropriation of Picasso's art by politics.
"The spectacle of the sky overwhelms me. I'm overwhelmed when I see, in an immense sky, the crescent of the moon, or the sun. There, in my pictures, tiny forms in huge empty spaces. Empty spaces, empty horizons, empty plains - everything which is bare has always greatly impressed me." - Joan Miró, 1958, quoted in Twentieth-Century Artists on Art.
In an interview with biographer Walter Erben, Miró expressed his dislike for art critics, saying, they "are more concerned with being philosophers than anything else. They form a preconceived opinion, then they look at the work of art. Painting merely serves as a cloak in which to wrap their emaciated philosophical systems."
In the final decades of his life Miró accelerated his work in different media, producing hundreds of ceramics, including the Wall of the Moon and Wall of the Sun at the UNESCO building in Paris. He also made temporary window paintings (on glass) for an exhibit. In the last years of his life Miró wrote his most radical and least known ideas, exploring the possibilities of gas sculpture and four-dimensional painting.
Throughout the 1960s, Miró was a featured artist in many salon shows assembled by the Maeght Foundation that also included works by Marc Chagall, Giacometti, Brach, Cesar, Ubac, and Tal-Coat.
The large retrospectives devoted to Miró in his old age in towns such as New York (1972), London (1972), Saint-Paul-de-Vence (1973) and Paris (1974) were a good indication of the international acclaim that had grown steadily over the previous half-century; further major retrospectives took place posthumously. Political changes in his native country led in 1978 to the first full exhibition of his painting and graphic work, at the Museo Español de Arte Contemporáneo in Madrid. In 1993, the year of the hundredth anniversary of his birth, several exhibitions were held, among which the most prominent were those held in the Fundació Pilar i Joan Miró, Barcelona, the Museum of Modern Art, New York, the Museo Nacional Centro de Arte Reina Sofía, Madrid, and the Galerie Lelong, Paris. In 2011, another retrospective was mounted by the Tate Modern, London, and travelled to Fundació Joan Miró and the National Gallery of Art, Washington, D.C.