Ernst Paar completed an apprenticeship as a lithographer in Graz and from 1922 attended the evening act at the state art school. After completing his apprenticeship, Paar moved to Germany, where he attended the Stuttgart Academy in 1926/27. In 1930, Paar went to Paris with his painter friend Hans Stockbauer and attended the Académie Julian there. In 1933 he moved to Vienna and worked as a graphic designer. At the same time, he made a name for himself as a member of the Graz Secession and the Hagenbund in Vienna with Cubist and New Objectivity images. After the uprising of the Social Democratic Protection Association in 1934, he moved in the resistance circle around the Styrian architect Franz Schacherl in Vienna. He was a member of the hanging commission in the Hagenbund and tried in vain to organize an exhibition of the Graz Secession in the Hagenbund. During the Nazi dictatorship he was drafted into service as a commercial artist. Nevertheless, he continued to work as a freelance artist and offered cultural resistance by continuing his modern style of painting. He was only able to exhibit once during the war, but this show was closed early due to stylistic deviations towards degenerate art. In 1943 he had to join the Wehrmacht. After the war, he worked as an assistant at the Academy of Applied Arts, but was fired in 1948 because he had published a caricature critical of the government. In 1950 he exhibited in a personal exhibition in the Neue Galerie Graz. In 1951 he was vice president of the artists' group “Der Kreis”, a very important artists' association in Vienna alongside the Art Club. In 1963 he received the Theodor Körner Prize and in 1965 the City of Vienna Prize for Applied Arts.