<p>This study presents a novel dynamic sustainable production-inventory model designed specifically for the fashion industry, distinguishing between traditional and eco-friendly product lines. Unlike existing models, it integrates three key levers—advance payment mechanisms, green investment decisions, and carbon emission penalties—into a unified optimization framework. The model seeks to maximize total profit while minimizing environmental impact, particularly carbon emissions, by incorporating a price- and investment-sensitive demand structure for eco-friendly garments. Advance payment acts as both a liquidity enhancer and an environmental financing mechanism, while green investment directly influences demand and emission intensity. Carbon penalties are imposed when total emissions exceed regulatory thresholds, reinforcing sustainable production. The model includes detailed cost components, such as production, holding, and emission costs. To identify optimal production rates, investment levels, and pricing strategies, two metaheuristic techniques—weighted particle swarm optimization (WPSO) and constriction factor PSO (CPSO)—are employed. Both methods converge to the same global optimum, yielding a maximum profit of INR 4471.0 while satisfying emission constraints. Sensitivity analysis confirms the model’s robustness against variations in key parameters. Overall, the proposed model offers actionable insights for fashion manufacturers seeking to align profitability with circular economy and climate-resilient objectives.</p>