A German Communist whose family had fled Hitler's Germany and who was educated in the Soviet Union, after World War II Leonhard became one of the founders and leaders of the German Democratic Republic until he became disillusioned and fled in 1949, first defecting to Yugoslavia and then moving to West Germany in 1950 and later to the United Kingdom.

In 1956 he moved to the United States, where he was a popular and influential professor at Yale University from 1966 to 1987, teaching the history of communism and the Soviet Union, topics about which he wrote several books.

From 1931, Susanne Leonhard and her son lived in the "Artists' Colony" in Wilmersdorf, Berlin, the home of many left-wing intellectuals.

[5] Wolfgang attended Karl Marx Grammar School and joined the youth organization of the Communist Party of Germany, the "Young Pioneers".

6) had been established in Moscow for Austrian and German orphans of fascism;[7] Leonhard lived there from September 1936 to August 1939, when it was closed a week after the Molotov–Ribbentrop Pact, following months of pressure after a number of residents were arrested in the so-called Hitler Youth Conspiracy.

Leonhard's mother was arrested by the secret police, NKVD, in October 1936, and had to do forced labour for the next 12 years, mainly in the camp of Vorkuta (see Gulag).

Some of his teachers and fellow students there were to be found in leading positions after 1945, such as Paul Wandel, Heinz Hoffmann and Markus Wolf in the GDR and Jakub Berman in Poland.

The eldest son of Yugoslav partisan leader Josip Broz Tito, Zarko, also attended the Comintern school at the time.

Like Anton Ackermann, Wolfgang Leonhard thought that the creation of a German socialist state would follow a more democratic pattern than the developments he had experienced in the Soviet Union.

On April 16, 1948, Walter Ulbricht gave a five-hour speech at the SED college outlining the plans for the Soviet-occupied sector.

He identified the SED as the future governing power and asserted that people should seek to reach their own goals through the state apparatus.

Yugoslavia had been expelled from Cominform, the successor organization of Comintern under Soviet leadership, and was establishing its own totalitarian type of socialism.

[20] In 1987, when West German President Richard von Weizsäcker visited the Soviet Union, Leonhard was able to return to that country for the first time since 1945.