Ernst Busch was born on January 22, 1900, in Kiel, Germany, to a working-class family. Initially trained as a mechanic, he worked at a shipyard before pursuing a career in acting and singing. Busch became a prominent figure in the Berlin Kabarett scene during the 1920s, known for his interpretations of political songs, especially those by Kurt Tucholsky. He starred in the original 1928 production of Bertolt Brecht's "The Threepenny Opera" and appeared in the 1931 film adaptation.

A committed communist, Busch joined the German Communist Party in 1919. He fled Nazi Germany in 1933, settling initially in the Netherlands and later living in Belgium, Zurich, Paris, Vienna, and the Soviet Union. In 1937, he joined the International Brigades during the Spanish Civil War, performing for volunteers and working for Radio Madrid.

During World War II, Busch was interned in France and later imprisoned by the Nazis until he was freed by the Red Army in 1945. After the war, he settled in East Berlin, where he continued his acting career and worked with Bertolt Brecht and Erwin Piscator at the Berliner Ensemble. Busch was also known for his recordings of workers' songs, including those by Hanns Eisler, and for his performance in Brecht's "Life of Galileo."

Busch was awarded the Lenin Peace Prize and remained a beloved figure in the German Democratic Republic until his death on June 8, 1980, in Bernburg, East Germany.