This article shares findings from a study that explored factors contributing to the development of a social work professional identity, with a particular focus on social work students undertaking field education placements in mental health settings. Social work identity is not well recognised or articulated by experienced practitioners, nor does it appear to be adequately emphasised in social work education and training programmes. There is limited research on social work identity in mental health settings and even less pertaining to students’ efforts to construct a professional identity in such paradigmatically unfamiliar environments. This qualitative study explored how students understand, experience and articulate their developing professional identity in mental health settings. Participants were interviewed towards the completion of seventy-day (500-hour) field placements. Findings highlight that students struggled to relate to the concept of a ‘social work identity’ and were unable to articulate what it might be or involve. Students were more at ease describing specific roles they performed during their placement. However, analysis of their reflections on what they observed, what they did during placement, and reflective or integrative opportunities, provided rich descriptions of a range of the factors contributing to and influencing their developing social work identity.