Health promotion research is deeply rooted in the principles and values of the health promotion movement and in the Alma-Ata Declaration’s drive towards a new concept of local health systems. Policies and strategies to improve population health by mobilizing local resources and actors are the central objects of investigation and are often subsumed into a larger body of studies that conducts population health intervention research. In this chapter, we reflect on an investigation (the CLoterreS project) of a policy instrument defined in the French national legislation to improve coordination and mobilization of the local actors to reduce inequities in health. We first present the key features of health promotion research and those of our object of investigation followed by an account of how the current context of health promotion research shaped our strategy to strengthen our capacity to study this object and inform policies. We then present some of our main results along with their impact on practice and policy. We found that our practitioner–researcher partnership contributed to enhancing interest for health promotion research and provided a new lexicon of actions at the local level and opportunities to intervene in different policy fora. This partnership also sets our project on a course, thus allowing to grab other research opportunities.