Education studies have repeatedly emphasized the crucial contribution of family-school-community partnership to children's academic and educational success, as well as to improving organizations and systems. Such partnership becomes even more complex when the child presents needs in several areas of development. In this context, it is essential that researchers work collaboratively with actors in the field, first to identify barriers to family-school-community partnership, and then to support the implementation of levers to overcome those barriers. In this research, we built upon an existing model, the Sunshine Model, and tested our enhanced model "in vivo" in three specialized schools in greater Montreal serving adolescents with developmental disabilities. Operationalization of the adapted model through participatory action research shows great promise for supporting professionals, not only in specialized but also in inclusive school settings, in grasping the multilevel dimensions--types and diversity of activities, partnership principles, interactional contextual factors-- that facilitate or impede family-school-community partnership.