Inspired by the contributions of Poul Kjaer and Kerry Rittich to this Special Issue, this article extends the reflection on the role and potential of law for social transformation. More specifically, I attempt to build on a revised framing of the constitutive role of law to draw the contours of a transformative instrumentalism, where law functions as an instrument for the articulation of political and social objectives. My account shifts the attention from transformative law’s form to its content, based on the premise that engagement with ‘political’ economy necessarily entails an engagement with the substantive standards that shape social relations of production and define the nature and extent of exploitation. Yet, I argue that the endorsement of law’s constitutive function and the turn to law’s content need not lead to the kind of instrumentalism that exhausts itself in particular policy reforms or prescriptions to assume control over processes of legal coding. Relying on a tentatively redrawn conception of the constitutive role of law that draws from both legal institutionalism and Marxist perspectives, I suggest that instrumentalism may instead be transformative by prioritising material ends, leaving open the question of the concrete legal and institutional forms that will materialise them. The directions of such transformative instrumentalism involve an element of ‘mobilisational democracy’ against the insulation of the economy from democratic control; reforms generative of collective subjects and centres of democratic power (‘non-reformist reforms’); and a focus on the planning and coordinating function of law among diverse – but united in their objective – legal rationales and institutional forms.