Polyethersulfone (PES) is a polymeric material that is commonly used due to its chemical resistance, high mechanical strength, and thermal stability. The improvement of PES hydrophilicity and anti-fouling properties can be facilitated by mixing additives into the polymer casting solution. This study involved the preparation and characterization of PES/pluronic F108/chitosan/reduced graphene oxide (rGO) nanocomposite nanofiltration membrane. The modified PES membrane was developed by employing the phase inversion method via immersion precipitation. The effect of varying concentration of rGO nanocomposite ranging from 0.05 to 0.20 wt% in the fabricated membrane was evaluated in terms of membrane pure water permeation (PWP), salt rejection, morphology, and hydrophilicity. Images obtained from scanning electron microscopy (SEM) showed increasing rGO nanocomposite concentration in the casting solution, resulted in the increase in membrane sub layer thickness, hydrophilicity, salt rejection, and improvement in the membrane pore structure. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of the hydrophilic functional group and chemical compound in the prepared membrane. PES with 0.20 wt% of rGO nanocomposite obtained the highest PWP at 28.64 (L/m2h) at 5 bar pressure, whereas the highest rejections of monovalent and multivalent salt were obtained by PES with 0.15 wt% rGO nanocomposite with 75% and 89% rejections, respectively at 5 bar pressure. This study shows that the utilization of rGO nanocomposite as an additive in the PES casting solution can enhance nanofiltration membrane performance and morphological structure.