This research proposal delves into the critical impact of project managers' leadership skills and competencies on achieving project efficacy, especially in projects with varying characteristics. The study examines the historical context, highlighting the evolution of project management and the necessity of leadership in complex business environments. It reviews existing literature, emphasizing leadership styles, emotional intelligence, and the competencies needed for project success. The research outlines its design, including data sources, research questions, and objectives, along with a conceptual framework and proposed methodology utilizing secondary data and MAXQDA software for analysis. The proposal also details the budget and schedule, aligning with the University of Adelaide's academic year, to provide a comprehensive foundation for understanding the importance of leadership skills in project management and achieving successful project outcomes in a global context.