The article traces the origins of the principle of subsidiarity within the Social Doctrine of the Church. It reviews key milestones from Pius XI’s Quadragesimo Anno to John Paul II’s Centesimus Annus, including John XXIII’s contributions. Furthermore, through authors like Tocqueville, Rosmini, and Sturzo, the author introduces a fruitful dialogue between the social magisterium and the Austrian School of Economics, demonstrating how the principle of subsidiarity acts as a barrier against the totalitarian drift of the state.