This snapshot presents the theory of change that guided the work of the ExCELS project. It shows (1) what can influence ECE leadership, (2) what leadership looks like by illustrating who leaders are based on formal and informal roles in decision-making, change, and improvement; what individuals bring to leadership; and what center staff do as leaders to promote quality and positive outcomes; and (3) what leadership can influence in terms of outcomes for center quality, staff, and children and families. (author abstract)