Efficiently planning and managing workforce is a challenge imposed on many companies, especially for those in the service industry. The target of an effective workforce management is to recruit, develop and deploy the right people at the right places at the right times to fulfill both organizational and individual objectives. In this paper, we propose a novel concept of “workforce supply chain” to address the workforce management issue by considering both the demand side issue, i.e., project management, and the supply side issue, i.e., the human resource management. We then use System Dynamics modeling technique to capture the causality relationships and feedback loops in the workforce supply chain with the merit of system thinking. The evaluation of System Dynamics-based simulation exposes dynamic behavior and workforce management system and shows how adaptive control can be applied to such system.