Building capacity to enhance health promotion intervention effectiveness is a desirable, difficult to achieve and rarely evaluated aspect of practice. This study aims to describe an approach for evaluating capacity building embedded in a state-wide health promotion intervention that had a primary objective of enhancing food literacy and secondary objective of building health promotion capacity. The multi-strategy rural food literacy intervention centred on a group-based, hands-on learning workshop series. Logic modelling, theory of change and clarification of the explicit assumption of the intervention relating to food literacy and capacity building objectives were documented. The evaluation approach acknowledged the complexity of the intervention that utilised a food literacy program as a vessel to build relationships, enabling capacity-building strategies over time, and used multiple forms of data to measure organisational, community and individual capacity. The development of a shared mixed method program evaluation plan was achieved through co-design. One-hundred and twenty-Two peer facilitators were trained across 81 communities and reported increases in self-efficacy for health promotion action. There was broad awareness and support for the program within the organisation. The majority (75%) of communities involved in the intervention implemented at least one health promotion activity, demonstrating some health promotion capacity gain.