The knowledge-based companies are among the main drivers of the knowledge-based economies. Therefore, it is important to study the reasons for their success. Among the affecting factors, organizational leadership and innovation leadership are very important. In this research, attempts have been made to investigate the successful leadership styles in accordance with the popular leadership styles, which were previously introduced in the literature. Regarding the purpose, this research is considered as developmental research and the data collection and analysis have been done via multiple qualitative case study methods. By selecting samples with maximum characteristics from among 186 profitable knowledge-based companies that still work with the original team, the theoretical saturation was finally achieved in the ninth and tenth case studies. The data extracted from the semi-structured interviews with 21 of the leaders and key employees of these companies and the content of the interviews were analyzed and the codes and categories were extracted and their relationship was identified. Finally, it has been shown that the inspirational motivation as one of the fundamental aspects of transformational leadership method is obvious in these companies, but charisma, individual considerations and intellectual stimulation are rare. In addition, despite observing some important aspects of “ initiating structure style” and "servant leadership style", these two styles are not dominant in the organizations, and in fact, a combination of components of these three styles ensures success in these companies.