Aim <p>Co-creation is gaining traction in the public sector as a useful approach for stimulating innovative solutions in a society facing limited public resources, complex problems, and rising public expectations. Although co-creation holds considerable potential, there is limited understanding of how the traditional roles that are found in the public sector are transformed in co-creation. The aim of this study was to investigate how changes in roles are perceived by stakeholders involved in public sector-driven co-creation of public health initiatives, and how these role transformations influence the dynamics among participants.</p> Subject and methods <p>We conducted group interviews with 56 stakeholders from different sectors (public, private, and nonprofit sectors and civil society), who participated in a project developing activity spaces in six Norwegian municipalities.</p> Results <p>Our findings reveal that all stakeholder groups experienced role transformations during the co-creation process. These role shifts shaped the stakeholders’ perceptions of their own influence, altered the distribution of tasks and responsibilities, and generated tensions regarding whose knowledge and expertise were recognized.</p> Conclusion <p>This study provides valuable insights for policymakers and practitioners aiming to improve co-creation processes for public health initiatives in the public sector. The results underscore the importance of designing co-creation efforts that ensure early and meaningful involvement, clearly allocate responsibilities, and recognize diverse forms of knowledge. This is essential for enabling all stakeholders to adopt new roles with clarity and confidence.</p>