Background <p>Research funders, such as the UK National Institute for Health and Care Research, are committed to capacity-building for the health and social care workforce in addition to that provided for doctors and dentists. Programmes designed to build capacity offer research training and collaborations with academia. This paper reports findings from a process evaluation of capacity-building research internships and predoctoral fellowships provided through a research-practice partnership in one region in England. The aim of the study was to explore experiences from multiple perspectives and ascertain factors influencing the development of research capacity and impact of the schemes.</p> Methods <p>A total of 29 individual qualitative, semistructured interviews were undertaken with (i) interns and predoctoral fellows (health, social care or quality improvement professionals based in the regional health and social care system), (ii) health and social care managers (mostly line managers of the interns and predoctoral fellows) and (iii) supervisors (university academics). Data analysis followed a thematic approach, informed by Cooke’s framework for the evaluation of research capacity-building.</p> Results <p>Our analytical framework was based on Cooke’s framework for research capacity-building; all six principles were relevant. (i) The schemes facilitated the building of skills and confidence and exposure to the academic research environment. (ii) The research facilitated was close to practice; trainees pursued their research interests sparked by their practice experience. (iii) The schemes fostered linkages, collaborations and partnerships by bringing together practitioners from the regional health and social care system with researchers at the university; many effective and enduring collaborations were forged. (iv) Trainees achieved dissemination and impact via publishing research and leveraging funding, generating outputs traditionally recognized as metrics of capacity-building success; they also created impact in practice. (v) In terms of continuity and sustainability, the schemes provided a first step in research for some and a next step for others. Trainees shared and cascaded newly acquired skills, coaching and encouraged practice colleagues to get involved in research. Programme infrastructure, including organizing staff cover and support from managers in practice, were necessary.</p> Conclusions <p>Our findings aligned with all of Cooke’s principles. Individual managerial support, infrastructure and research culture were crucial for the development of research capacity. Subsequent research should develop theories of change and apply them in evaluations of research capacity-building.</p>