BACKGROUND: The ability to sustain comprehensive primary health care (PHC) services in the face of change is crucial to the health of rural communities. This paper illustrates how one service has proactively managed change to remain sustainable. METHODS: A 6-year longitudinal evaluation of the Elmore Primary Health Service (EPHS) located in rural Victoria, Australia, is currently underway, examining the performance, quality and sustainability of the service. Threats to, and enablers of, sustainability have been identified from evaluation data (audit of service indicators, community surveys, key stakeholder interviews and focus groups) and our own observations. These are mapped against an overarching framework of service sustainability requirements: workforce organisation and supply; funding; governance, management and leadership; service linkages; and infrastructure. RESULTS: Four years into the evaluation, the evidence indicates EPHS has responded effectively to external and internal changes to ensure viability. The specific steps taken by the service to address risks and capitalise on opportunities are identified. CONCLUSIONS: This evaluation highlights lessons for health service providers, policymakers, consumers and researchers about the importance of ongoing monitoring of sentinel service indicators; being attentive to changes that have an impact on sustainability; maintaining community involvement; and succession planning.