The engagement of frontline practitioners in the production of research-derived knowledge is often advocated. Doing so can address perceived gaps between what is known from research and what happens in clinical practice. Engagement practices span a continuum, from co-production approaches underpinned by principles of equality and power sharing to those which can minimalize practitioners' contributions to the knowledge production process. We observed a conceptual gap in published healthcare literature that labels or defines practitioners' meaningful contribution to the research process.We, therefore, aimed to develop the concept of "Researcher Practitioner Engagement" in the context of academically initiated healthcare research in the professions of nursing, midwifery, occupational therapy, physiotherapy, and speech and language therapy. Guided by Schwartz-Barcott et al.'s hybrid model of concept development, published examples were analyzed to establish the attributes, antecedents, and consequences of this type of engagement. Academic researchers (n = 17) and frontline practitioners (n = 8)with relevant experience took part in online focus groups to confirm, eliminate, or elaborate on these proposed concept components. Combined analysis of theoretical and focus group data showed that the essence of this form of engagement is that practitioners' clinical knowledge is valued from a study's formative stages. The practitioner's clinical perspectives inform problem-solving and decision-making in study activities and enhance the professional and practice relevance of a study. The conceptual model produced from the study findings forms a basis to guide engagement practices, future concept testing, and empirical evaluation of engagement practices.