This article argues that the socio-environmental issues that emerged in the 1970s have been addressed from three different levels of ecclesial reflection and praxis: 1) the official magisterium: conciliar, pontifical, and episcopal; 2) non-magisterial epistemic institutions; and 3) charitable and advocacy networks. The institutional diversity of the Church made possible the reception, reflection, formulation, modulation, and transmission of the sustainability challenge in a dynamic that shows that Catholic Social Teaching has its genesis and development in the broader framework of Christian Social Thought and Praxis.