[1] After the war, he went to Leipzig and worked as an actor and lecture artist, joining the Communist Party of Germany in 1929.

He became a member of the International Brigades in the Spanish Civil War from 1937 to 1939, where he was active as a front correspondent and wrote battle poems.

[2] In July 1937 he attended the Second International Writers' Congress, the purpose of which was to discuss the attitude of intellectuals to the war, held in Valencia, Barcelona and Madrid and attended by many writers including André Malraux, Ernest Hemingway, Stephen Spender and Pablo Neruda.

[1] After Germany attacked the Soviet Union, Weinert sided with the Soviets and began creating propaganda to encourage soldiers in the Wehrmacht to abandon their positions[4] using methods such as poems printed on handbills that were thrown off behind the German lines as well as making pleas to them via the radio and shouting slogans from the rubble of Stalingrad.

Regardless, he served actively as vice-president of the Central Administration for National Education in the Soviet Occupation Zone.

[1] He was cremated and honoured with burial at the Memorial to the Socialists (German: Gedenkstätte der Sozialisten) in the Friedrichsfelde Central Cemetery, Berlin.