Principal's hands-on strategies reflecting their theories of changing have a substantial effect on the development of their schools and on how the large-scale reform takes root. The study explores five comprehensive school principals' leadership strategies during a large-scale school reform in Finland. The principals' strategies in the middle of reform acknowledged the process nature of leading and involved coherence-making. The inclusive and learning-oriented strategies were applied quite consistently in terms of the horizontal, but not so much in the vertical coherence-making. Exclusive strategies we used to decrease teachers' workload. Principals' theories of changing seem to focus on creating and protecting teachers' opportunities for meaningful learning.