The World Health Organization’s Tailoring Immunization Programmes approach was used to develop a new strategy to increase child vaccination coverage in a disadvantaged community in New South Wales, Australia, including reminders, outreach and home visiting. After 18 months, the strategy hasn’t been fully implemented. A process evaluation was conducted to identify barriers and facilitators for research translation. Participants included child health nurses, Population Health staff, managers and general practitioners. The Capability–Opportunity–Motivation model of behaviour change (COM-B) was used to develop questions. Twenty-four participants took part in three focus groups and four interviews. Five themes emerged: (i) designing and adopting new ways of working is time-consuming and requires new skills, new ways of thinking and changes in service delivery; (ii) genuine engagement and interaction across fields and institutions helps build capacity and strengthen motivation; (iii) implementation of a new strategy requires clarity; who’s doing what, when and how?; (iv) it is important not to lose sight of research findings related to the needs of disadvantaged families; and (v) trust in the process and perseverance are fundamental. There was strong motivation and opportunity for change, but a need to enhance service capability. Areas requiring support and resources were identified.