Abstract Background Evidence based practice enhances service planning and delivery, clinical decision making and patient care. However, health professionals often lack the time and opportunity to access or generate evidence. Research capacity building is thus an important mechanism for improving health service delivery. This study evaluates the effectiveness of a UK-wide Nurse and Allied Health Professional musculoskeletal research internship programme in which graduates applied to undertake their internship through one of five Higher Education Institutions. The evaluation explores the experiences of interns and their mentors. Methods Sixteen new graduates completed the internship programme (September 2015 – August 2018). Twelve interns and thirteen mentors participated in the evaluation. The evaluation used qualitative asynchronous email-based interviews to explore the experiences of interns and mentors. Interpretive phenomenological analysis of coded transcripts identified principal themes. Results Early research outputs from the interns include three peer reviewed publications and 21 conference abstract presentations. Two interns were in full time research at the time of interview or had a research component in their clinical role. Nine interns in clinical posts disclosed plans to return to research in the near future. Seven themes were identified: the impact on interns’ careers; personal impact (for example, influence on self-confidence); impact on clinical practice; drivers for applying; intervention design (for example, attitudes concerning the timing and duration of the intervention); mentorship and networking (including general support provided and quality of career advice); challenges. Conclusion The internship programme is an effective model in building research capacity in musculoskeletal research for Nurses and Allied Health Professionals, influencing careers, building confidence and improving clinical practice. The internship programme has the potential to be replicable to other clinical contexts nationally and internationally.