This paper presents a comprehensive mathematical framework for dynamic manpower planning aimed at supporting sustainable organizational growth. The proposed model integrates workforce inflows, internal transitions, skill development, attrition, and demand variability within a multi-period planning horizon. Using systems of difference equations and optimization techniques, the framework enables organizations to forecast workforce requirements, evaluate policy alternatives, and balance cost efficiency with long-term sustainability. The model accounts for both quantitative and qualitative aspects of manpower, allowing decision-makers to align human resource strategies with organizational objectives while adapting to external and internal changes. The applicability of the framework is demonstrated through theoretical analysis, highlighting its potential to improve workforce stability, productivity, and resilience. This research contributes to the existing manpower planning literature by offering a flexible, analytically robust approach suitable for modern, growth-oriented organizations.