Objective: This study investigated the efficacy of a two-component professional development approach to improving school wellness in Pennsylvania secondary schools. Design: Circle of Wellness (CoW), a year-long, two-phase programme, involved providing Whole School, Whole Community, Whole Child (WSCC) workshops to Pennsylvania school staff and administrators, followed by personalised technical assistance to facilitate the implementation of wellness initiatives. Setting: The workshops were provided in-person, with follow-up technical assistance (e.g. phone calls, zoom meetings, real-time editing sessions via Google Drive) delivered remotely. Method: Workshops featured expert presentations, activity stations, and physical resources to meet all 10 components of the WSCC model. After workshop completion, research staff provided support to promote school staff adoption of a wellness action plan grounded in WSCC components. Participants then completed post-programme evaluations rating satisfaction and success with the implementation of their action plans. Results: In a final programme evaluation, 70% of the respondents reported bringing about healthy changes as a result of participating in the CoW programme (n = 28). In addition, 100% of the school representatives reported that attending the workshop and participating in the programme were a worthwhile experience (n = 40). Conclusion: Professional development opportunities such as the CoW, which includes follow-up guidance and resources, were well received by school staff, and the understanding gained through participation in such programmes contributed to the sustainability of wellness initiatives.