Introduction: The purpose of this review is to explore research literature beyond music therapy and music medicine studies that addresses healthcare musicians' work in hospitals. Music-related and intersectoral collaboration in contemporary healthcare may appear as if all music practitioners, including music therapists and healthcare musicians, maintain the same professional stance, harmonized goals, and orientations in their work. We argue that this is not the case, either in practice or in research, and therefore this complex field is in need of conceptual clarification as well as educational guidance. Method: A systematic search of peer-reviewed literature with PRISMA yielded 16 studies relating to healthcare musicians' work in somatic hospital settings. These studies were analysed with the quality appraisal tool CASP, utilizing the descriptive statistics and thematic approach, and assessed with the ROBIS tool. Results: Within the scope of the review, the quality of the studies, as well as the reporting of methods and analysis, were very diverse. The review indicates that the hybrid professional work of healthcare musicians in hospitals does not stem from the practices of music therapy. Instead, the healthcare musicians' work draws from different historical, societal, and philosophical contexts, developed mainly in the twenty-first century. Discussion: Despite the rich descriptions of the healthcare musicians' practice and work presented in this review, it remains questionable whether the profession of healthcare musician is already internationally established. However, the emerging movement of expanding professionalism, which healthcare musicians are a part of, needs to be addressed more clearly in practice, research, and education.