Haug coined the term commodity aestheticism (Warenästhetik, in German). His Critique of Commodity Aesthetics has been translated into numerous languages. Since 1958, he has also been the chief editor of the journal Das Argument, the successor to the Zeitschrift für Sozialforschung (1933–1941). The latter journal was housed at the Institute of Social Research (founded by Max Horkheimer). In a sense, Haug thus maintains a direct line from the Frankfurt School. Since 1994, Haug also edits the Historisch-kritische Wörterbuch des Marxismus and edited The Historical Critical Dictionary of Marxism, published by the Berlin Institute of Critical Theory.
With his wife he was one of the first to become members of the new left wing party Die Linke in 2007.
Haug is a member of the Scientific Advisory Board of ATTAC.