Abstract Background Outside-of-school-hours-care (OSHC) services are well positioned to influence the health behaviours of 489, 800 Australian children, and are an important setting for health promotion given the current rates of childhood overweight and obesity and associated health risks. OSHC Professionals are ideally placed to become positive influencers in this setting, although they may require training and support to confidently perform this role. This study piloted a multifaceted intervention strategy to increase OSHC Professional’s confidence and competencies, to support a health promoting OSHC environment with a nutrition and physical activity focus. Methods A mixed methods approach was used. Nineteen OSHC Professionals participated in the study, including a face-to-face workshop, supported by a closed Facebook group and website. Role adequacy (self-confidence) and legitimacy (professional responsibility) were measured pre and post workshop and evaluated using non-parametric statistics. Facebook interactions were monitored, and four participants undertook qualitative exit interviews to discuss their experiences with the intervention. Results Pre-workshop 68% of participants had not received any OSHC-specific health promotion training. Post-workshop significant improvements in confidence about menu planning, accessing nutrition information, activities and recipes was observed (P