This paper reports data from three sources showing young people’s positive responses to the population-wide Act-Belong-Commit mental health promotion campaign: (i) impact on 14-25 year old participants in a peer-educator workshop program; (ii) impact on 11-14 year old student participants in an adaptation of the campaign in secondary schools (the ‘Mentally Healthy Schools Framework’); and (iii) impact of the population wide media-based campaign on 18-24 and 25-34 year olds in the general population (versus those 35+ years). Overall, these findings support the conclusion that mental health promotion interventions can be based on underlying constructs relevant across the lifespan and then tailored for specific ages and settings rather than requiring the development of separate, distinct programs based on different constructs for younger age groups.