The leadership support provided by Heads of Schools (HoS) influences teachers in secondary schools in Tanzania. Several drivers influence the leadership support in enhancing teachers’ work performance (TWP) in Tanzanian secondary schools. Therefore, the paper intends to address the drivers that influence leadership support provided to teachers in secondary schools in Tanzania. Employing a qualitative exploratory design, the research conducted in-depth interviews with 76 participants (Heads of Schools and teachers) across the Iringa and Njombe regions. The study found that the influence of leadership support is divided into two distinct categories: external and internal drivers. External drivers include the pursuit of better student performance, strict directives from higher authorities (such as District Education Officers), the need to “market” or advertise the school (particularly in the private sector), and the attainment of institutional visions. Internal drivers comprise the personal fulfilment of responsibilities, the desire to retain the headship position, and the attainment of legacy status. It was further found that external drivers outweigh internal ones, suggesting that most HoS provide support based on external pressure or mandates rather than personal initiative. This threatens the sustainability of the provided support. The HoS need to develop internal motivation geared toward supporting teachers. This will end up contributing to achieving Sustainable Development Goals, especially Goal 4(Quality Education).