Digitalizing school is a process that comes with challenges. It requires strategic leadership and transformational change to work processes. Nevertheless, some succeed, and it is useful to understand what makes for success. This paper studies the challenges of leading digitalization of education in a city which decided to implement an IT-supported method for teaching literacy in primary schools. The method required transformational change; teachers not only had to learn to use technologies, they also had to review their pedagogy. This study is guided by the Diffusion of Innovation theory and draws on interviews with school principals. We find that the critical factors relate to the communication channel, the social system within and across schools, and the time perspective.