<p>Sustainability has become a central concept in global policy agendas, corporate strategies, and civil society discourse. Yet, despite its ubiquity, the term often functions as a vague ideal, encompassing divergent-and at times conflicting-interests. This study addresses the critical gap in understanding how sustainability operates not merely as an environmental or developmental goal, but as a discursive construction that shapes political identities and power relations. Drawing on post-structuralist theory, particularly the works of Foucault, Derrida, Laclau, and Mouffe, the research investigates how sustainability functions as a hegemonic identity by marginalizing alternative narratives and securing broad ideological consensus. Employing critical discourse analysis, the study examines policy documents and public narratives from the European Union, the United Nations, and Turkey to trace how sustainability is articulated, institutionalized, and contested in different governance settings. The findings indicate that sustainability has evolved into an “empty signifier”-a flexible concept that unites diverse agendas under a common rhetorical umbrella. While this discursive openness facilitates global alignment, it also allows for co-optation, symbolic politics, and the suppression of transformative alternatives. Emerging critiques such as degrowth and climate justice movements reveal the fragility of this consensus and highlight growing resistance to technocratic and market-driven sustainability models. By situating sustainability within a broader field of ideological struggle, the study underscores its unstable and contested nature. Recognizing the discursive mechanisms that elevate sustainability to hegemonic status opens space for more pluralistic, democratic, and justice-oriented sustainability imaginaries. These insights carry important implications for rethinking policy frameworks and grassroots strategies in the face of ecological and political crises.</p>