This study examines the features of school leadership as it evolved in an upper secondary school attempting to enhance school improvement through a dedicated team of developmental leaders. We study the team leadership's tools and design over one school year and report on the evolution of a collective approach to leadership for school improvement. Researchers in a formative intervention research project supported the change process. Cultural-historical activity theory and a set of new technologies inspired the intervention design. The study describes how conceptions and practices of leadership gradually emerged as a collective and distributed approach to leading educational change and school improvement. In particular, new tools and designs for school team leadership were explored and implemented. The study addresses the need to develop shared and collaborative conceptions of leadership in schools. The study concludes that careful planning and skilful orchestration of human, cultural and technological resources are needed in order to make sustainable improvements in schools.