Social marketing campaigns promoting moderate to vigorous physical activity (MVPA) may be more successful when associated with strong brands. Little is known regarding how brand constructs such as brand resonance may be related to MVPA and its antecedents (e.g., having a physical activity identity). A better knowledge of these constructs and their relationships can reveal how to strengthen brands to make them more useful for interventions. The purpose of this study was to test a model linking ParticipACTION (a Canadian social marketing organization) brand constructs (brand affective attitude, identification, resonance), MVPA antecedents (behavioral affective attitude, identity), and MVPA. This study used a cross-sectional online survey design with a representative Canadian adult sample of 1,475 people (M age = 49.36; 49.1% female). Path analysis was conducted to test the model. Overall, the model fit the data well, demonstrating positive associations between brand affective attitude and identification, identification and resonance, resonance and both behavioral affective attitude and identity, behavioral affective attitude and both identity and MVPA, and identity and MVPA. The results suggest that building brand resonance is important for linking branding to MVPA variables. Brand management activities designed to target brand affective attitude may be crucial to helping people feel strong resonance with a brand in a way that supports behavior change.