The difficulty in attracting graduates of nursing programmes into mental health nursing (MHN) remains an ongoing challenge. Moreover, it is frequently claimed that undergraduate nursing students do not always regard MHN favourably for future employment. Although undergraduate nurses are employed as assistants in nursing (AIN) in mental health settings, there is no published research exploring their role, the career trajectory into MHN, or its effectiveness as a recruitment strategy. In this paper, we draw on the literature to delineate factors that might contribute to the desire of AIN to work in MHN. Nine factors were identified: acceptance by nurses, fitting in with the culture, managing the workload, developing a realistic appraisal of the effectiveness and limits of psychiatry, constructive learning from direct interpersonal interactions with clients, practising communication skills, being supported in a structured way, working with positive role models, and the overall quality of the employment setting. A comprehensive understanding of these factors can enhance the experience of undergraduate nursing students working as AIN, and potentially increase recruitment into MHN.