Schumacher was the son of a salesman. When World War I started, he left school to join the German army. In December 1914, he was badly hurt. His arm had to be removed. After this, he went back to school in Berlin to study Law and politics. While there, he became a socialist. In 1924, he was elected to the legislature in Württemberg. He became the SPD leader for Württemberg in 1928. In 1930, he was elected to the national legislature, the Reichstag.