The current study examines senior school leaders' theories of action driving their decision-making around how they manage departments and distribute leadership to department heads. Based on a thematic analysis of transcripts of interviews with the principal, head of the curriculum unit, and two department heads from nine high schools, four approaches for managing departments were identified: (a) quasi self-managing units; (b) hierarchical managerial control; (c) participatory management; and (d) transitioning from hierarchical control to incipient participatory management. All approaches, to varying degrees, involved hierarchical managerial control and, to a greater or lesser extent, department heads participated in decision-making. At the centre of the distinct patterns for the distribution of leadership associated with each management model was a concern for aligning teachers' improvement priorities. These approaches are examined through a distributed leadership lens in terms of their potential affordances and constraints for strengthening the contributions of departments to school improvement processes. The main conclusion is that variations in how senior leaders manage departments for the distribution of leadership need to be understood in the context of a school's history and culture.