Purpose: The purpose of this article is to present the results obtained from the investigations that have been carried out within the International Successful School Principalship Project (ISSPP) project in the Spanish for social justice. Design/methodology/approach: Twelve case studies have been carried out within the three lines of research proposed by ISSPP: successful principals, underperforming principals and principal leadership identity. All but one school were in challenging contexts. The methodological approach followed is based on multiple perspective case studies using a mixture of qualitative methods (interviews, focus groups and observations). Findings: Results show that successful principals not only believe in social justice through simple empathy with the concept of social justice, but also use strategies that combine transformational and instructional leadership processes and manage to reverse the bad situation of their disadvantaged schools, seeking excellence from equity. The leadership identity of successful principals is characterized to look to the future with hope, adopting a realistic utopian attitude to interpret their surrounding reality. Originality/value: From the case studies carried out, valuable information is obtained, which helps to understand the possibilities of implementing the ISSPP successful school leadership model in heterogeneous and disadvantaged context for equity and social justice.