From 1921 to 1925 Suhrkamp worked as dramatic adviser and director at the Landestheater Darmstadt. In 1932 he joined the S. Fischer Verlag. In 1936 he bought the part of the S. Fischer Verlag, which could not be transferred by Gottfried Bermann Fischer into exile. Peter Suhrkamp led the publishing house till April 1944, when he was arrested by the Gestapo. Sculptor Arno Breker interceded with the authorities and saved his life.
After the German surrender, Suhrkamp received on 8 October 1945 the first publishing license from the British Military Government in Berlin and began the rebuilding of the company. He cooperated with Bermann Fischer. 1950 a rift between Suhrkamp and Bermann Fischer led to the creation of Suhrkamp Verlag and the reestablishment of the S. Fischer Verlag in Frankfurt am Main.