BACKGROUND: Many low-income and crises-affected countries like Sierra Leone struggle with the recruitment and retention of their health professionals, particularly nurses and doctors. There are multiple factors that influence the 'recruitment to retention' pipeline. The first stage of an exploration into the issues influencing the availability of qualified health care workers may focus on the aspects which influence their entry into relevant educational programmes. This paper explores the reasons given by junior doctors in Sierra Leone for wanting to become a doctor. It also describes entry procedures into undergraduate medical education. METHODS: In-depth interviews were conducted with purposively sampled junior doctors (n = 15) from the only medical school in Sierra Leone in October 2013. Digital diaries and two follow-up interviews were used to explore their evolving career experiences and aspirations until November 2016. In addition, semi-structured interviews with key informants (n = 20), including senior teaching staff at the medical school (n = 7), were conducted. Thematic analysis was used to explore linkages and themes across cases. RESULTS: Six themes were identified. The most commonly mentioned reasons for wanting to become a doctor were a desire to help (theme 4) and the influence of family and friends, via role modelling (theme 2) and verbal encouragement (theme 3). Other motives were an interest from a young age (theme 1), being attracted by the job prospects (theme 5), and having an intellectual and science capacity (theme 6). Junior doctors gave at least two and up to six reasons for applying to enter the medical profession. Doctors were allowed entry to the medical school largely based on their previous academic performance. CONCLUSIONS: This study showed that multiple reasons underlie the decision to apply for entrance to medical school and the decision to enter medicine is complex. These findings may inform the review of future admission procedures by the medical school in Sierra Leone and similar settings, which is a crucial step in addressing the human resource needs for healthcare that currently exist.