Every moment counts (EMC) is a multi-tiered mental health promotion initiative designed to build the capacity of practitioners to address the mental health needs of children and youth in school settings. This study evaluated the impact and cultural relevance of EMC workshops in supporting practitioners to apply a public health approach to children's mental health in Aotearoa New Zealand. A longitudinal mixed methods design employed a survey and semi-structured interviews to evaluate the applicability, impact and cultural relevance of the EMC workshops. Themes identified from participants' reflections on their experiences of implementing EMC represented everyday practices at individual, team, and organizational levels. Specifically, intersectorial collaboration was perceived as beneficial. There is a call to action for practitioners to work more cohesively and interprofessionally, at policy and practice levels, to effectively promote children's mental health and achieve equitable health and well-being outcomes. Communities of practice offer a potential mechanism to support translation of knowledge into practice in schools. Application of a public health approach to children's mental health in schools, facilitated by the EMC initiative, is applicable and positively impacts outcomes in Aotearoa New Zealand, with some modifications needed to better fit the cultural context.