The field of leader development has recently begun to focus more on the role of pre-adult leadership experiences in shaping leader development. However, research has largely neglected to account for children’s and adolescents’ agency in shaping their own leader development, instead focusing on external drivers of such development (e.g., parents, schools). This integrative conceptual article provides a model for leader development from childhood through adolescence, drawing on insights from the cognitive and social child development literature. This model focuses on the reciprocal influences of agency, early leadership experiences, and foundational socio-cognitive skills, including theory of mind, metacognition, self-regulation, and autobiographical reasoning, to foster growth and complexity in leadership skills and mindsets. In addition, the enabling forces that influence the early development and expression of agency, socio-cognitive skills, and leader mindsets are described.