School leaders work in increasingly complex systems. Alongside leading learning, they daily navigate the needs and expectations of educational departments, teachers, students, parents, society, and themselves. Leadership can therefore be a dynamic vocational calling, but studies show that principals' professional agency, career sustainability, and wellbeing are diminishing. This Element brings a fresh perspective to how educational leaders can be better served and supported by collaborative, co-agentic partnerships at this time. It makes the case for professional supervision, a practice commonplace in clinical and pastoral professions that offers facilitated, action-oriented attention to the interplay of role, 'soul', and context. As a practice-based primer, this Element reclaims supervision against outdated associations with performance management by drawing on interdisciplinary research and the authors' own experience as supervisor partners with principals. It proposes a new schema of professional supervision in education informed by curiosity, unlearning, resonance, and attunement in a rapidly changing world.