The operationalisation of environmental sustainability is critically impeded by fragmented theoretical foundations and an insufficient interrogation of the ontological tensions and epistemological conflicts between its constitutive dimensions. This chapter resolves this deficit by presenting a critical meta-analysis that synthesises the paradigm’s philosophical evolution, its competing theoretical frameworks, and the practical antagonisms inherent in its implementation. The analysis commences with a genealogical examination of the concept’s emergence from Malthusian limits to growth through to the Brundtland formulation and contemporary planetary boundaries discourse. It then systematically contrasts dominant theoretical lenses; including weak versus strong sustainability paradigms, ecological modernisation theory, and political ecology—all to illuminate their divergent policy implications. The chapter also employs a critical tripartite framework to dissect the often-contradictory logics underpinning the three core pillars of sustainability: the economic (focused on capital accumulation, externalities, and decoupling), the social (centred on equity, justice, and human capabilities), and the environmental (defined by carrying capacity, resilience, and ecosystem services). This deconstruction reveals intrinsic governance dilemmas. The discussion subsequently evaluates prevalent strategic approaches; from techno-optimistic innovation to degrowth—while foregrounding the structural, institutional, and socio-political challenges that impasse their efficacy. By providing this rigorous theoretical scaffolding and confronting its pragmatic paradoxes, the chapter provides scholars and practitioners with the clear conceptual acuity needed to move beyond surface-level actions to develop consistent and thoughtful sustainability practices.