Internationally, large scale reform is big business and yet relatively little is known about the senior administrators who manage and lead local educational reform implementation. In this first of a two-part article, the authors focus on the role of senior administrators in facilitating large-scale reform in one Ontario, Canada school district (LEA). The provincial government reform initiatives facing senior administrators and school districts in Ontario are massive, including the forced amalgamation of different boards of education. The studied school district, Thames Valley District School Board (Thames Valley), was the result of the provincial decision to amalgamate four districts into one. While this action was large, it was just one of many externally imposed reform efforts that have been the subject of the authors' research since 2000. This two part paper is limited to reviewing 2002/2003 data on the leading and learning of senior administrators as they facilitated large-scale reform across the amalgamated school district. This article provides a real life example of how senior administrators can lead change by reforming their own practices and can directly impact on student performance. [For Part 2, see EJ805862.] (Contains 1 table and 1 footnote.)