To develop and support an environment where the work of an initial dynamic leader is continued beyond the leader’s tenure, attention must be paid to the challenges of sustainability and adaptation. Sustainability—the likelihood that the overall system can regenerate itself toward improvement—is a continuous process, not a single event. Only leaders who are equipped to handle a complex, rapidly changing environment can implement reforms that lead to sustained improvement in student achievement. Just as leadership is complex and dynamic, so is context. The nature of the link between leadership and context determines whether school improvement will be sustainable over the long term.