Ernst invented frottage because he was staring at a wooden floor. He was in a hotel room in 1925, looking at the grain of the floorboards, and saw figures and landscapes in the patterns. He placed paper over the surface and rubbed it with graphite. The textures that emerged, wood grain transformed into forests, oceans, and strange organic forms, became the basis of his painting technique for the next decade.

He was born in Brühl, near Cologne, and studied philosophy and art history at the University of Bonn. He had no formal art training. He saw a Picasso exhibition, joined the Rhineland Expressionists, served in the German army during the First World War (artillery), and emerged with what he described as a compulsion to find something beyond rational thought. Dada gave him the method. Surrealism gave him the framework.

His collage novels, made from cut-up Victorian engravings reassembled into dreamlike narratives, are among the most original works of the twentieth century. Une Semaine de Bonte (A Week of Kindness, 1934) is a series of 182 collages arranged in five chapters, each associated with an element and a day of the week. The imagery is violent, erotic, and funny. The source material, melodramatic Victorian illustrations, is treated with deadpan seriousness.

He married four times. His second wife was Peggy Guggenheim (briefly). His fourth was the painter Dorothea Tanning. He moved to America during the war, lived in Sedona, Arizona, and then returned to France. He died in Paris in 1976, the night before his eighty-fifth birthday.