Leadership in small and medium enterprises (SMEs) has remained an under-researched area in the management literature, especially in developing countries such as Nigeria. SME owner-managers in Nigeria lacked in-depth understanding of their leadership style to objectively evaluate its implication on long-term performance and growth of their enterprise. The purpose of this qualitative multiple-case study was to explore the experiences of SME owner-managers in Nigeria to gain an in-depth understanding of their leadership style and its implication for long-term performance and growth of their enterprise. The conceptual framework for this study was anchored in two key concepts; leadership styles and leadership in SMEs, with the full range leadership model as the theoretical foundation. The research question sought to explore the role of SMEs owners and managers leadership styles in the long-term success of their enterprise. Interview data were collected from 6 SME owner-managers who employ less than 200 employees within the manufacturing, education, and trading sectors. The cross-case synthesis technique was used for data analysis which allowed for within-case analysis and cross-case comparisons. Findings from this study showed that Nigerian SME owner-managers do not follow any specific leadership style. They exhibited few characteristics of transformational and transactional leadership behaviors, leaning more to transactional leadership. This study has significance for positive social change by providing insights on how leadership styles can improve the performance and sustainability of Nigerian SMEs, thus increasing their capacity to create employment.