In the United Kingdom, approximately a third of people with dementia live in long-term care facilities for adults, the majority of whom are in the last years of life. Working arrangements between health services and care homes in England are largely ad hoc and often inequitable, yet quality end-of-life care for people with dementia in these settings requires a partnership approach to care that builds on existing practice. This paper reports on the qualitative component of a mixed method study aimed at evaluating an organisational intervention shaped by Appreciative Inquiry to promote integrated working between visiting health care practitioners (i.e. General Practitioners and District Nurses) and care home staff. The evaluation uses a social identity approach to elucidate the mechanisms of action that underlie the intervention, and understand how organisational change can be achieved. We uncovered evidence of both (i) identity mobilisation and (ii) context change, defined in theory as mechanisms to overcome divisions in healthcare. Specifically, the intervention supported integrated working across health and social care settings by (i) the development of a common group identity built on shared views and goals, but also recognition of knowledge and expertise specific to each service group which served common goals in the delivery of end-of-life care, and (ii) development of context specific practice innovations and the introduction of existing end-of-life care tools and frameworks, which could consequently be implemented as part of a meaningful bottom-up rather than top-down process. Interventions structured around a Social Identity Approach can be used to gauge the congruence of values and goals between service groups without which efforts to achieve greater integration between different health services may prove ineffectual. The strength of the approach is its ability to accommodate the diversity of service groups involved in a given area of care, by valuing their respective contributions and building on existing ways of working within which practice changes can be meaningfully integrated.