Isaiah Berlin’s ‘Two Concepts of Liberty’ was a milestone in the development of modern political theory, with his advocacy of negative freedom supporting the neoliberal demand for ‘freedom from’ the state. This article defends the conception of positive freedom by calling on the neglected insights of the sociological tradition. I demonstrate how Marx, Durkheim and Simmel all understood freedom to be a socially conditioned phenomenon, with ‘freedom from’ being an idealist fiction (Marx), and a recipe for anomie (Durkheim) and loss of meaning (Simmel). I argue, however, that positive freedom as it was theorised by the classical sociologists must be distinguished from the more fashionable idea of individual self-realisation and self-identity, a notion equally susceptible to idealist constructions, and one increasingly targeted by Foucault-inspired critics. Instead I draw on Hannah Arendt and André Gorz to show how positive freedom should be theorised as a worldly, conflictual, and pre-eminently political affair.