Gustav Metzger (1926–2017) has been described as ‘the conscience of the art world’ for the consistently political content of his art and his commitment to political activism on the subject of nuclear weapons, capitalism and environmentalism. Metzger’s artistic output from the late 1950s onwards reflects a theory of art as both aesthetic form and social action and identifies him as a key precursor of activist art. This article considers the inherent interdisciplinarity of Metzger’s practice as it evolved during this early period between the late 1950s and early 1970s in relation to his agenda of social engagement.