This paper draws on coupling and systems frameworks to investigate the relationships between two English Multi-Academy Trusts (MATs) and their member schools in how decisions are made around budgeting, recruitment processes, and curriculum and assessment. Findings demonstrate when and under what conditions executive leaders and specifically CEOs, as primary agents of coupling, created greater consistency across schools either through centralization or deliberate alignment of school improvement planning, while operating within their complex institutional environments. Implications for practice, policy, and research on system-wide reform are discussed.