He published works in English and German at home and abroad, and despite longstanding criticism of the GDR remained a committed socialist.

[2] In 1935, he received a grant from a Jewish student association, and went to the United States to continue his degree at the University of Chicago, which he completed in 1936 with a dissertation on Heinrich Heine.

After the newspaper ceased publication in November 1939, Heym worked as a freelance author in English, and achieved a bestseller with his first novel, Hostages (1942).

These experiences formed the background for a later novel, The Crusaders, and were the basis for Reden an den Feind (Speeches to the Enemy), a collection of those texts.

[5] After the war Heym led the Ruhrzeitung in Essen, and then became editor in Munich of Die Neue Zeitung, one of the most important newspapers of the American occupying forces.

Because of his refusal to soften his critical stance toward Nazism and the German elites that had collaborated with it and his refusal to begin to discreetly weave doubts about Soviet intentions into his editorials,[6] Heym was transferred back to the U.S. toward the end of 1945 and in 1951, fearing investigation by the House Un-American Activities Committee as the hunt for Communists led by Senator Joseph R. McCarthy reached a crescendo, Heym left the United States with his American wife, Gertrude Gelbin, whom he married in 1944.

In the years after reunification, Heym was critical of what he saw as the discrimination against East Germans in their integration into the Federal Republic, and argued for a socialist alternative to the capitalism of the reunited Germany.

As President by right of age of the Bundestag he held the opening speech of the new Parliament in November 1994, but resigned in October 1995 in protest against a planned constitutional amendment raising MP expense allowances.

Heym died suddenly of heart failure in Ein Bokek in Israel whilst attending a Heinrich Heine Conference.