Medical leadership is increasingly considered as crucial for improving the quality of care and the sustainability of healthcare. However, conceptual clarity is lacking in the literature and in practice. Therefore, a systematic review of the scientific literature was conducted to reveal the different conceptualizations of medical leadership in terms of definitions, roles and activities, and personal–and context-specific features. Eight databases were systematically searched for eligible studies, including empirical studies published in peer-reviewed journals that included physicians carrying out a manager or leadership role in a hospital setting. Finally, 34 articles were included and their findings were synthesized and analyzed narratively. Medical leadership is conceptualized in literature either as physicians with formal managerial roles or physicians who act as informal ‘leaders’ in daily practices. In both forms, medical leaders must carry out general management and leadership activities and acts to balance between management and medicine, because these physicians must accomplish both organizational and medical staff objectives. To perform effectively, credibility among medical peers appeared to be the most important factor, followed by a scattered list of fields of knowledge, skills and attitudes. Competing logics, role ambiguity and a lack of time and support were perceived as barriers. However, the extent to which physicians must master all elicited features, remains ambiguous. Furthermore, the extent to which medical leadership entails a shift or a reallocation of tasks that are at the core of medical professional work remains unclear. Future studies should implement stronger research designs in which more theory is used to study the effect of medical leadership on professional work, medical staff governance, and subsequently, the quality and efficiency of care.