Sustainable cell tower design is essential for minimizing the environmental footprint of expanding telecommunication networks, which traditionally prioritize signal coverage over sustainability. This study addresses this gap by proposing a holistic framework that integrates standardized sustainability metrics, advanced energy management systems, and modular design principles. The research aims to minimize environmental footprint while ensuring scalability and cost-effectiveness. A multi-criteria decision-making (MCDM) model is developed to evaluate designs based on energy consumption, carbon emissions, lifecycle costs, and adaptability. The model was validated against operational tower data with a 5.4% Mean Absolute Percentage Error (MAPE). Simulations and a detailed retrofit case study demonstrate significant and substantiated improvements in energy efficiency, increased by up to 30%, carbon emissions reduced by 60%, operational costs lowered by over 65%, and lifecycle costs are lowered by 20%. Furthermore, the modular designs prove highly adaptable, extending infrastructure lifespans and minimizing material waste. This research provides a scalable, cost-effective solution for greener telecommunication infrastructure, aligning with global sustainability goals. The framework bridges theory and practice, offering a robust foundation for broad industry adoption, with future work focused on pilot testing and socio-economic considerations for equitable implementation.