The aim of the research is to pinpoint which leadership-related factors affect school success, specifically focusing on features and strategies used by the principals. The work follows the International Successful School Principalship Project methodology in two case studies in Andalusia (Spain). Both schools (with differentiated environments) are classed by the research as 'invisible or visible school', depending on the evolution and recognition of their success. Case A is a high-performing and declining school (invisible) and Case B is a low-performing and rising school (visible). The results emphasise the importance of the socioeconomic and cultural school context and the characteristics and type of leadership exercised by principals in their relationships with the environment, academic outcomes of the pupils and the school's innovation process. The principal's leadership is also crucial for acknowledgement of school results.