This study explores the durability of eco-friendly mortar mixes incorporating copper slag (CS) and glass powder (GP) under aggressive environmental conditions. Glass powder was used to replace cement at 5%, 10%, 15%, 20%, and 25%, while copper slag replaced sand at 0% to 50% in 10% increments.  Fixed cement to fine aggregate ratio of 1:4 was maintained throughout the study. The research focuses on evaluating the long-term performance of these modified mortars under aggressive exposure conditions, such as marine and sulphate-rich environments. Mechanical strength was assessed through compressive strength tests, while Sustainability under harsh exposure conditions was evaluated using sulphate, acid resistance tests, carbonation depth analysis and rapid chloride penetration test (RCPT). The results demonstrated that optimal combinations, particularly those with 15–20% GP and 30–40% CS, significantly improved resistance to chemical attacks and reduced penetrability.  Microstructural analysis using SEM and XRD confirmed the formation of additional C-S-H gel, denser internal structure, and reduced portlandite content, highlighting the pozzolanic contribution of GP and the filler effect of CS. The modifications enhanced durability and minimized deterioration, demonstrating the viability of GP and CS as sustainable alternatives for durable mortar incorporating industrial by-products.