Purpose: The purpose of this paper is to explore the role of the secondary Head of Department (HoD) in leading teams producing exceptional education outcomes in Years 7-10 in New South Wales (NSW, Australia) government schools. Design/methodology/approach: Sites where exceptional educational outcomes were believed to be occurring were selected using a variety of data including performance in standardised tests, public examinations, various value added measures and nominations from various stakeholders. Sites were of two types: subject departments responsible for teaching certain subjects and teams responsible for cross-school programmes in Years 7-10. Sites were selected to be broadly representative. Some schools had more than one site, e.g. Mathematics and Student Welfare. A total of 50 sites across NSW from 38 secondary schools were studied. Findings: With both subject departments and teams responsible for cross-school programmes, leadership was found to be a key factor in the achievement of exceptional educational outcomes. Analysis of data revealed certain qualities, attributes and practices of the HoD of these schools, which are explored, central to which is a focus on students and their learning. Research limitations/implications: HoDs were those of secondary schools from one state educational system. Practical implications: Despite the pressures of the secondary HoD role, the HoDs studied had been able to lead and facilitate teams that were thriving when others struggle to perform. Whilst innate, personal qualities are important, much of what these HoDs possessed and demonstrated had been learned from others. Originality/value: Detailed case studies have provided an examination of HoD leadership effectiveness in a wide range of contexts, with much commonality revealed. Thus, the study can inform future professional learning for secondary HoDs and possibly other middle managers in education. It may also have value for HoD selection. (Contains 1 note.)