Mentoring schemes continue to increase within organisations and rely on attracting and retaining motivated volunteers. At the same time, mentoring is also becoming embedded within professional frameworks and discipline experts are being enlisted in formal schemes to widen their involvement in supporting novices in their professional development. This phenomenological study follows the experience of four mentors from two professions, who were actively mentoring in their first formal scheme. Findings show that even experts in a professional field can return to the experience and anxieties of early practice and that formal schemes and training may not sustain commitment to mentoring in the future, unless they provide opportunity for reflective development. A conceptual model for mentor development is proposed which offers an approach to support the experiential transition from ‘professional-as-mentor’ to ‘professional mentor.’