A very intriguing question in Open Source software (OSS) development is: why there are only a few open source projects succeed, while the majority of projects never do. In this research, we examine the factors that may influence the performance of OSS projects. We particularly focus on the OSS’s core developers’ role in the project’s success. Extant research has yet to distinguish core developers and non-core developers from the community at large. The different roles of the core developers and non-core developers in OSS projects’ success still remain unclear. Our research contributes to the literature by separating the core developers from the development forces in general and empirically examining the core developers’ importance. Drawing the evidences from our extensive dataset of 300 open source projects, we demonstrated that core developers’ leadership and project advocation are crucial in determining the fate of the OSS projects. Our research could provide better understanding of OSS sustainability. It could also give practical advice to the OSS community on how to make the project successful.