Introduction: Improving and maintaining the health and wellbeing of older people requires integrating actions to optimise their intrinsic capacity. The Indigo 4Ms tool for health workers was codesigned by older people and health and social care staff across northeast Victoria. It aims to improve, maintain or slow declines in intrinsic capacity by assessing and acting on four interconnected areas: what matters, medication, mobility, and mental wellbeing. Method: The Indigo 4Ms study is a hybrid type 2 effectiveness-implementation mixed-methods collective case study designed to determine the effectiveness of the Indigo 4Ms tool for health workers in improving multidisciplinary comprehensive care planning for older people in rural primary care settings. Five rural health services in northeast Victoria are implementing the Indigo 4Ms approach within their primary health services. At the end of the first year of implementation, drawing on insights from Soft Systems Methodology, semi-structured interviews were conducted with sixty-six primary health care staff across the five sites. Findings: Analysis of interview data highlighted the complex and changing environments in which primary health clinicians operate, which mitigate against a focus on intrinsic capacity. Despite a person-centred approach to care, funding models and medical record technologies structure the older person-clinician relationship, with a focus on the delivery of aids, equipment and services rather than on improving or maintaining intrinsic capacities. Conclusion: Improving the health and wellbeing of older people requires health systems to support health promotion along side service delivery.