Objective: This study examines CEO competency's impact on business performance in startup companies, particularly in Indonesia. It also explores the mediating role of business networks in this relationship. Theoretical Framework: The study builds on theories of leadership competency and network theory to investigate how the competencies of startup CEOs influence both business performance directly and indirectly through the development of business networks. Method: The study employs Structural Equation Modeling-Partial Least Squares (SEM PLS) to analyse data collected from 300 respondents drawn from a population of 2,419 startup companies in Indonesia. Results and Discussion: The findings reveal that CEO competency significantly positively affects both business performance and the establishment of business networks. Furthermore, business networks also positively influence business performance. The study confirms that business networks serve as a crucial mediating factor in the relationship between CEO competency and business performance, strengthening the overall performance of startup companies. Research Implications: These results offer practical insights for startup CEOs, suggesting that enhancing leadership competencies and fostering business networks can significantly improve business outcomes. The findings also contribute to the broader understanding of how leadership skills in startups can mitigate the high failure rates in this sector. Originality/Value: This research is the first to empirically investigate the role of CEO competency in startup business performance in Indonesia, specifically focusing on the mediating role of business networks. Its novelty lies in addressing startups' high failure rates through the lens of leadership and networking.