Kurt Rosenfeld was born in Marienwerder, Germany, in 1891. After obtaining a doctorate in law he worked as a lawyer in Berlin. Rosenfeld held left-wing views and worked as defence lawyer for radicals such as Rosa Luxemburg and Leo Jogiches.

Rosenfeld served in the German Army during the First World War. After the war he joined the Independent Socialist Party and was minister of justice in the Prussian provisional government during the German Revolution.

After the demise of the Independent Socialist Party Rosenfeld became one of the leaders of the left-wing of the Social Democratic Party (SDP) in the Reichstag. He was also co-founder of Der Klassenkampf (1927) and he Socialist Workers Party (1931).

When Adolf Hitler came to power in 1933 Rosenfeld emigrated to the United States. Kurt Rosenfeld died in 1943.