Open-graded bituminous course (OGBC) plays a vital role in road construction by providing excellent drainage capabilities, reducing noise pollution, enhancing skid resistance, reducing splash and spray, and improving overall road safety. OGBC is a porous asphalt layer since its air voids will be range of 18–22%. The laboratory study goal was to determine the characteristics of the OGBC mix with different fibers, both in partial and full replacement of filler. Therefore, during the process, two types of different fibers, namely, coir fiber as natural fiber and polyester fiber as synthetic fiber, and groundnut shell powder (GSP) for filler replacement were taken into consideration. For determining optimal fiber content, fibers were taken at various doses, such as 0.15%, 0.3%, and 0.45% by weight of mixture. The range of binder content levels was 5% to 6.5%, with increments of 0.5%. Air voids (%), draindown (%), Cantabro abrasion particle loss (%), and indirect tensile strength (ITS) of the compacted mixtures were all determined along with Fourier transform infrared spectroscopy (FTIR) analysis for fiber-reinforced OGBC mixes. The results of the trial show that optimum fiber content was found to be 0.3% for both fibers. Coir fiber with GSP as full replacement of filler shows the improved durability of 29.57% at 5% bitumen content and 74.35% at 6.5% bitumen content compared to coir fiber with conventional filler of 26.15% at 5% bitumen content and 65.37% at 6.5% bitumen content. Voids in coarse aggregates in dry-rodded condition (VCAdrc) were found to be 44.17% while voids in compacted mix (VCAmix) decreased from 40.56% at 5% binder content to 36.53% at 6.5% with full filler replacement and coir fiber also followed a similar pattern, reducing from 41.13% to 35.94%. Polyester fiber with conventional filler showed superior performance, with tensile strength ratio (TSR) of 87.47% compared to coir fiber with conventional filler with TSR of 85.18%. Overall performance of OGBC mix with GSP as full filler replacement to conventional filler was found to be improved by 30%. Hence the use of agro-based filler material, i.e., groundnut shell powder(GSP), is viable for replacement of conventional fillers in OGBC mixtures and can contribute to resource efficiency and waste reduction.