<p>This article investigates a two-echelon sustainable supply chain model that integrates economic and environmental objectives under market uncertainty. Unlike conventional approaches that treat demand as a price-driven function, the proposed model considers multi-factor demand influenced by selling price, lead time, marketing effort, and competitor pricing, represented using an interval type-2 trapezoidal fuzzy number. Sustainability is embedded through a three-stage inspection and rework mechanism, as well as explicit modeling of carbon emissions from production and transportation. The model also integrates strategic marketing efforts and competitor pricing analysis to enhance competitiveness, while adopting a backorder policy to manage shortages during lead times effectively. The model aims to maximize the profit function while ensuring environmental compliance, validated through efficient analytical optimization techniques, and evaluating performance via comparative numerical experiments under deterministic and fuzzy environments. Moreover, sensitivity analysis validate the model’s reliability across various system parameters. The results suggest that incorporating these factors improves overall profitability and sustainability performance compared to traditional approaches.</p>