The purpose of this research is focused on the performance evaluation of Gilsonite-modified binders (GMBs) and high-aged binder (HAB) content (more than 40 %) with and without the use of WMA additive. Accordingly, GMBs and GMB-WMA samples were prepared by combining PG52–28 softer binders and 4 %, 8 %, 12 %, and 16 % of Gilsonite with and without Sasobit. The results indicated that increasing the Gilsonite increases the viscosity, improves the rheological behavior, reduces the rutting, and increases the fatigue life Although higher Gilsonite content has performance advantages, it also has negative effects in terms of performance and low temperature/fatigue resistance. While the use of a composite-modified binder showed an effective way to overcome these limitations and optimize the overall performance characteristics of HAB. Adding 4, 8, 12, and 16 Gilsonite combined with Sasobit increased the rutting resistance by 46 %, 64 %, 80 %, and 87 % respectively, compared to the base binder. Combining Sasobit with 8 and 12 Gilsonite upgraded the performance of the base binder from PG58–22 to PG70–16 and PG76–10. The fatigue life of the AB/G+WMA containing 4, 8, 12, and 16 Gilsonite was 2.11, 2.25, 2.52, and 2.38 times greater than the base binder, respectively. Based on optimization results, Gilsonite/Sasobit combinations were recommended for different traffic conditions: G15.3+S1.8 for heavy traffic areas, G11.6+S1.9 for tropical regions, and G6+S2 for cold climates. The goal was to optimize the blends to leverage the benefits of Gilsonite while mitigating any drawbacks, depending on the specific climate and traffic conditions. The study demonstrates that the synergistic use of Gilsonite and Sasobit can significantly enhance the performance characteristics of asphalt binders, enabling tailored solutions for different applications and environmental conditions.