As they speculate on possible careers within diverse musical communities, many undergraduate music students go through a pivotal identity transition and need both guidance and leadership. Instrumental teachers can potentially discover a wealth of opportunities to extend their influence on their students and lead them through periods of personal and professional transformation. Based on a case study, this chapter explores the construction of professional identity experienced by a first-year undergraduate piano student in a United Kingdom music conservatoire, and ways in which his piano teacher leads that reflective process. Findings suggest that students’ professional identity negotiations involve a reflective process of envisioning a future career, which draws from subjective and objective factors as well as internal and external dialogues with instrumental teachers. These are balanced against each other in order to arrive at a vision that is grounded in the student’s personal interests and musical identity. The case study highlights a potential leadership role for instrumental and vocal teachers in supporting the transition and identity work of student musicians.