This thesis offers a comprehensive account of Ralf Dahrendorf’s liberal political thought between the early 1950s and the late 1980s, with particular emphasis on the role that his methodological ideas played in his conception of politics. It argues that materialist conceptions, borrowed from Karl Marx and other materialist theorists, informed his liberal outlook throughout his career, transcending his early abandonment of political socialism. Situating Dahrendorf within a tradition of debate about necessity and contingency in German social thought from the end of the First World War to the Positivism Dispute of the late 1950s and early 1960s and the cultural turn of the 1970s and the 1980s, the work studies his attempt to overcome the social-scientific ideas of Talcott Parsons and other structural-functionalists and to recast sociology as a causality-oriented discipline that takes interests and social structure rather than ideas and values as its subject. This also affected Dahrendorf’s academic politics. Examining his role in the foundation of the University of Constance between 1964 and 1966, it shows how an anti-idealist critique of German higher education and political culture informed his attempt to create an institution for the social sciences that could break the perceived dominance of the humanities and overcome the central role of Law departments in the formation of the Federal Republic’s elite. The final two chapters discuss Dahrendorf’s engagement with neoconservatism and neoliberalism. Covering his interaction with scholars such as Daniel Bell and Samuel Huntington at settings including the London School of Economics and Political Science and the Trilateral Commission in the wake of the student movement, it discusses the development of his ideas vis-à-vis an emerging consensus that politics had turned into a cultural – rather than socio-economic – conflict. Finally, the thesis discusses Dahrendorf’s critique of Friedrich Hayek, Thatcherism, and constitutional economics during the 1980s. Here, it highlights a divergence between Dahrendorf’s agonistic liberalism and a new liberalism built on the assumption that the vast influence of ideas meant that politics was highly contingent and unpredictable. Combining the history of political thought and the history of the social sciences, this thesis revises established readings of Dahrendorf as a straightforward ‘Cold War liberal’. By doing so, it provides a new perspective on the history of liberalism and political thought more broadly before and after the paradigmatic shifts of the ‘cultural turn’.