The leadership roles of subject coordinators, by and large, have remained less explored especially in the developing countries. Consequently, their involvement in school improvement s virtually unknown. It was this gap in the existing literature, as well as the apparent insignificance of the position/role of subject coordinators in school improvement, that initiated this study. The present study examines a subject coordinator's leadership roles for school improvement in one junior boys' secondary school in Pakistan. The purpose is to look at the what and how of his leadership roles. Also explored are the facilitating and hindering factors encountered during the performance of these roles. The research uses the qualitative approach. It is a case study using multiple sources of data including primary and secondary sources. The primary data was collected through semi-structured interviews, informal conversations and observations. The secondary data source was office documents. The study reveals that the subject coordinator had a very minor, almost non-significant, role at the strategic level, where school directions are set. His roles tend to be concentrated at the second - operational level, and the third - personal level. The factors that facilitated his leadership role enactment included, his personal interest, selected school structure, and outside school change factors. Prominent among the factors that hindered his performance were the lack of certain specific skills, and heavy workloads of other teachers. For further research, a network analysis of intradepartmental, interdepartmental and interschool relationships, and their impacts on subject coordinators' leadership roles is suggested.