Introduction: Until recently, public policies have paid little attention to promoting the health of middle-aged adults through a population-based, multifactorial approach, even though health indicators for this demographic are cause for concern and this stage of life presents an opportunity to initiate behavioral changes before diseases develop. In this context, Santé publique France, supported by its steering and dialogue committee, has decided to develop an advocacy initiative aimed at stakeholders working in and for local communities. Study objective: To develop an “advocacy” framework with multi-stakeholder development steps necessary to identify perceptions, perceived health issues, and the roles that stakeholders play in local communities, as well as existing health promotion tools and strategies. To this end, Santé publique France conducted a qualitative survey of local stakeholders through semi-structured interviews and implemented stakeholder consultation processes. Results: The chosen methodology aims to transfer epidemiological data, promote key actions identified through the qualitative survey, and highlight the essential role played by stakeholders working in and for local communities. It highlights the complexity of the population-based approach to middle-aged adults in a context of responsibilities at multiple levels, a characteristic of public health policies. Discussion: The results confirm the relevance of an advocacy approach to encourage local stakeholders to work toward improving the health of middle-aged adults, particularly those who are socioeconomically disadvantaged.