Understanding causal mechanisms for implementation strategies is a priority for implementation and health promotion research. Logic models are helpful for understanding and illustrating mechanisms through which implementation strategies operate. Little guidance exists for developing logic models for existing implementation strategies. We demonstrate how to use Implementation Mapping (IM) in a retrospective manner to develop an IMap Logic Model for a social-emotional learning program implemented at Boys & Girls Clubs of Greater Houston (BGCGH). To inform logic model development, we used qualitative interview data (from implementers) and conversations with program organizers. To develop the logic model, we specified the most accessible information, beginning with the program and health-related outcomes. We then specified the implementation strategies and implementation outcomes, followed by change methods (i.e., theoretical techniques that influence positive change in determinants), practical applications (i.e., specific techniques for operationalizing change methods), and determinants (factors that influence implementation) and other contextual factors. The effectiveness outcomes for the program were to improve emotion regulation and social skills among youth. Clinician implementers delivered the program and BGCGH club directors and staff supported delivery. The implementation strategies were (1) group leader trainings; (2) implementation guide; (3) BGCGH staff training; (4) needs assessments (via site visits); (5) follow-up meetings; and (6) pilot program check-in meetings. Collectively, the strategies used various practical applications (e.g., scenario discussions, reviewing procedures) to operationalize change methods (e.g., active learning, participatory problem solving) to address determinants (e.g., knowledge, interorganizational relationships). The strategy set out to improve implementation behaviors (e.g., delivering program components as prescribed) and implementation outcomes (e.g., fidelity). The developed IMap Logic Model can be used to inform implementation evaluation efforts by helping identify outcomes, mediators, and moderators. The logic model can also be used to identify gaps that, if addressed, can help ongoing implementation and scale-up efforts.