PurposeChildren in majority world countries (MWC) have high rates of unmet mental health needs, with limited access to specialist resources. Integration of child mental health in existing psychosocial care can improve provision. Through a Train-the-Trainer (ToT) cascade approach, this study aimed to provide a framework for such integration in resource-constrained communities in Karachi, Pakistan and to establish hindering and enabling factors.Design/methodology/approachEight practitioners attended a child mental health ToT program, including training on a five-domain service transformation framework. Trainers co-designed and implemented interventions that integrated child mental health knowledge and skills on each domain. These were attended by 136 end-users (youth, parents, teachers, managers), of whom a sub-sample of 47 stakeholders, as well as the trainers, attended focus groups on their experiences. Data were analysed through a thematic codebook.FindingsEstablished themes reflected common ingredients across all domains/interventions that were deemed important for child mental health care integration. These included child-centric approaches, positive parenting, community mobilization and systemic changes.Originality/valueIntegrated child mental health care informed by the Train-of-Trainer approach can be a useful model for resource-constrained MWC contexts. Integrated interventions should be co-produced with communities.