Sport event studies have demonstrated that relevant stakeholders must share objectives and coordinate efforts to leverage a large-scale sport event to secure positive legacies. However, the challenging and complex task of collaboration between networks of diverse organizational stakeholders to secure legacies has received little scholarly attention. In this conceptual paper, the authors explore, through a political economy lens, differences between the political economies of sports and sport events pertaining to mass sport participation legacies. The authors focus on the mesolevel and consider how divergences in political economy elements—structure and context, stakeholders and ideas/incentives, and bargaining processes—influence the likelihood of mass sport participation legacies from large-scale sport events. The authors suggest a need for event legacy stakeholders to engage more meaningfully with the complexities surrounding securing mass sport participation legacies. In addition, they provide pragmatic, actionable implications for policy and practice to assist stakeholders in addressing the challenges they face to maximize legacy outcomes.