Sustainability is now among the hegemonic discourses used by government to construct problems and policy beyond the environmental domain. Detached from its origins, it functions as an ‘empty signifier’ whose flexibility and ambiguity can be harnessed in policy‐making and political debate. This article uses an Australian case study to show how sustainability discourse was mobilized to justify reversing a previous decision and raise the age at which the publicly funded aged pension could be accessed. Overall, it contributes to understanding how hegemonic intervention is accomplished by tracing discursive processes over time and amongst different texts, helping to identify shifts and turning points in trajectories of policy reform and political debate. I conclude by arguing that the use of sustainability discourse warrants particular critical attention because it signals broader difficulties in imagining alternative collective futures and considering the costs and consequences arising from current arrangements.