This paper is based on a Greek research project aiming at exploring the process of introduction and management of school innovation. Recent research on school innovation has shown that factors such as the role and the leadership style of the school principal influence the effective application of an innovation. The paper analyzes the data from two whole-day primary schools. Both case studies produce examples of transactional leadership, although the first study describes an authoritarian and control-oriented style and the second study explores a facilitative one, in the context of a school in which participatory structures have been introduced. It then goes on to examine specific strategies and related practices identified with leadership concept; this concept consists of a principal’s control orientation (i.e. teacher compliance to principal-determined goals) for the first study and an empowerment orientation (i.e. teacher involvement in formal and informal decision-making) for the second study. Observations, interviews and questionnaires with the principals and teachers, examination of school records and history have been selected as research tools to focus on the leadership approach as a key factor that affects: a) the process of innovation and b) teachers’ actions and response to the adoption of an innovation. Knowing that less emphasis on a “power over” approach and more reliance on a “power through” and “power with” approach to leadership creates a more motivational, productive and humane school culture, the underlying question is how schools might move to a democratic, empowering form of leadership in which power is shared throughout the school.