Background <p>People with cognitive impairment face several challenges during hospitalisation. Insufficient attention to person-centred care often means that individual needs are not recognised, which can lead to complications and adverse outcomes such as falls and a decrease in the nutritional status. To promote person-centred care on hospital wards, nurses acting as change agents possessing both clinical expertise and leadership skills are a key factor. We aimed to develop a complex person-centred care intervention for people with cognitive impairment delivered by Expanded Practice Nurses in acute care hospitals and to derive tailored implementation strategies.</p> Methods <p>This study used a multi-method-design. We performed two systematic reviews aiming to synthesise existing evidence on advanced nursing roles and factors influencing role implementation. To explore the setting and target groups, we conducted two surveys on the scope of practice of Expanded Practice Nurses and on attitudes of health care professionals towards advanced nursing roles in Germany. The results guided two expert workshops to model the intervention and prioritise implementation strategies using participatory principles. We created a logic model to depict underlying processes and contextual factors of the developed complex intervention.</p> Results <p>Fourteen intervention components form the complex intervention and reflect the tasks of the Expanded Practice Nurse within the interprofessional team. We defined nine components directly related to patients, five system-related tasks to promote person-centred care at an organisational level, and described opportunities for adapting the role to different contexts. Implementation strategies target qualifying the Expanded Practice Nurse, engaging the interprofessional team and people with cognitive impairment, as well as familiarising with local relationships and structures.</p> Conclusions <p>The comprehensive intervention development results in a detailed role description as well as implementation strategies allowing adaptation to different acute care contexts, especially in countries in an early stage of development of Advanced Practice Nursing. The developed nursing role is a key to promote person-centred care in the interprofessional team. By developing a person-centred culture on the wards, individual needs of people with cognitive impairment can be identified and addressed in time, which can lead to a reduction in complications and an improved hospital experience for patients.</p>