Max Ernst (/ɜːrnst/; German: [ɛʁnst] 2 April 1891 – 1 April 1976) was a German-born painter, sculptor, printmaker, graphic artist, and poet. A prolific artist, Ernst was a primary pioneer of the Dada movement and surrealism in Europe. He had no formal artistic training, but his experimental attitude toward the making of art resulted in his invention of frottage—a technique that uses pencil rubbings of textured objects and relief surfaces to create images—and grattage, an analogous technique in which paint is scraped across canvas to reveal the imprints of the objects placed beneath. Ernst is noted for his unconventional drawing methods as well as for creating novels and pamphlets using the method of collages. He served as a soldier for four years during World War I, and this experience left him shocked, traumatised and critical of the modern world. During World War II he was designated an "undesirable foreigner" while living in France.

Ernst was born in Brühl. He began painting in 1909 while studying at the University of Bonn, and later joined the Die Rheinischen Expressionisten group of artists. Ernst's work often featured ironic juxtapositions of grotesque elements with cubist and expressionist motifs. He had a fascination with birds, often including his alter ego, Loplop, a bird, in his work. He eventually settled in France and achieved financial success in the 1950s. He died in Paris on 1 April 1976.

Max Ernst was born in Brühl, south of Cologne, the third of nine children of a middle-class Catholic family. His father Philipp was a teacher of the deaf and an amateur painter, a devout Christian and a strict disciplinarian. He inspired in Max a penchant for defying authority, while his interest in painting and sketching in nature influenced Max to take up painting.

In 1909, Max Ernst enrolled in the University of Bonn, to read philosophy, art history, literature, psychology, and psychiatry. He visited asylums and became fascinated with the art work of the mentally ill patients; he also began painting that year, producing sketches in the garden of the Brühl castle, and portraits of his sister and himself. In 1911, Max befriended August Macke and joined his Die Rheinischen Expressionisten group of artists, deciding to become an artist.

In 1912, Max Ernst visited the Sonderbund exhibition in Cologne, where works by Pablo Picasso and post-Impressionists such as Vincent van Gogh and Paul Gauguin profoundly influenced him. His work was exhibited that year together with that of the Das Junge Rheinland group, at Galerie Feldman in Cologne, and then in several group exhibitions in 1913. In his paintings of this period, Ernst adopted an ironic style that juxtaposed grotesque elements alongside Cubist and Expressionist motifs.

In 1914, Ernst met Hans Arp in Cologne. The two became friends and their relationship lasted for fifty years. After Ernst completed his studies in the summer, his life was interrupted by World War I. Ernst was drafted and served both on the Western and the Eastern Fronts. The effect of the war on Ernst was devastating; in his autobiography, he wrote of his time in the army thus: "On the first of August 1914 M[ax].E[rnst]. died. He was resurrected on the eleventh of November 1918". For a brief period on the Western Front, Ernst was assigned to chart maps, which allowed him to continue painting. Several German Expressionist painters died in action during the war, among them August Macke and Franz Marc.

In 1918, Ernst was demobilised and returned to Cologne. He soon married art history student Luise Straus, of Jewish ancestry, whom he had met in 1914. In 1919, he visited Paul Klee in Munich and studied paintings by Giorgio de Chirico. In the same year, inspired by de Chirico and mail-order catalogues, teaching-aide manuals and similar sources, he produced his first collages (notably Fiat modes, a portfolio of lithographs), a technique which later dominated his artistic pursuits. Also in 1919, Ernst, social activist Johannes Theodor Baargeld and several colleagues founded the Cologne Dada group. In 1919–20, Ernst and Baargeld published various short-lived magazines such as Der Strom, die Schammade and organised Dada exhibitions.

Ernst and Luise's son Ulrich 'Jimmy' Ernst was born on 24 June 1920; he later would also become a painter. Ernst's marriage to Luise was short-lived. In 1921, he met Paul Éluard, who became a lifelong friend. Éluard bought two of Ernst's paintings (Celebes and Oedipus Rex) and selected six collages to illustrate his poetry collection Répétitions. A year later the two collaborated on Les malheurs des immortels and then with André Breton, whom Ernst met in 1921, on the magazine Littérature. In 1922, unable to secure the necessary papers, Ernst entered France illegally and settled into a ménage à trois with Éluard and his wife Gala in the Paris suburb of Saint-Brice, leaving behind his wife and son. During his first two years in Paris, Ernst took various odd jobs to make a living and continued to paint. In 1923, the Éluards moved to a new home in Eaubonne north of Paris, where Ernst painted numerous murals. The same year his works were exhibited at Salon des Indépendants.