Although interventions targeting the health of students in schools are becoming common, few studies have examined how health messages operate at the group level in school environments. This study examines the effects of message-based health interventions (extrinsic vs. intrinsic goal framing) in group environments (exergame competitive vs. exergame noncompetitive) on eliciting attitudes and intentions toward physical activity among children and adolescents. We conducted a 7-week school-based intervention program involving 336 children and 259 adolescents in Singapore in which pre- and post-intervention responses were recorded. Our findings revealed the difference in responses between child and adolescent groups. Children who participated in noncompetitive exergames with extrinsically framed health messages and those who participated in competitive exergames with intrinsically framed health messages demonstrated more favorable attitudes toward physical activity. However, the same effects were absent in our adolescent group. These findings suggest that the integration of exergames into competitive and noncompetitive environments can serve as a gateway to traditional physical activity in schools when strategically combined with intrinsically and extrinsically framed messages. Practical and theoretical implications for schools and health educators are discussed.