BackgroundThe Enhanced Health for Care homes (EHCH) framework is an innovative response to provide more proactive, preventative approaches to care for residents living in care homes. It involves co-producing a shared vision with primary care. As part of EHCH a UK clinical commissioning group supported GP’s in two localities to implement their preferred delivery approach involving a new Frailty Nurse-led (FN-led) model in care homes alongside an existing General Practitioner-led (GP-led) model. This paper focuses on implementation of the new FN-led model.MethodsA qualitative study design was adopted. Forty-eight qualitative semi-structured interviews were undertaken across six care home sites in a Northern locality: three implementing the FN-led and three engaged in an existing GP-led model. Participants included residents, family members, care home managers, care staff, and health professionals working within the EHCH framework.ResultsTwo overarching themes were generated from data analysis: Unanticipated implementation issues and Unintended consequences. Unsuccessful attempts to recruit Frailty Nurses (FN) with enhanced clinical skills working at the desired level (UK NHS Band 7) led to an unanticipated evolution in the implementation process of the FN-led model towards ‘training posts’. This prompted misaligned role expectations subsequently provoking unexpected temporary outcomes regarding role-based trust. The existing, well understood nature of the GP-led model may have further exacerbated these unintended consequences.ConclusionWithin the broader remit of embedding EHCH frameworks, the implementation of new FN roles needed to evolve due to unforeseen recruitment issues. Wider contextual factors are not in the control of those developing new initiatives and cannot always be foreseen, highlighting how wider factors can force evolution of planned implementation processes with unintended consequences. However, the unintended consequences in this study highlight the need for careful consideration of information dissemination (content and timing) to key stakeholders, and the influence of existing ways of working.