The dispersion of filler in a polymer matrix has a great effect on the structural-property relationship of the formed composite. In this context, surface modification of reduced graphene oxide (RGO) by hyperbranched polyester (PES) has been performed to facilitate its incorporation in polycaprolactone (PCL) matrix by melt blending technique. The structure of the modified reduced graphene oxide (mRGO) was confirmed by Fourier transform infrared (FTIR), and its morphology was studied with transmission electron microscope (TEM). Three main formulations, PCL/RGO and PCL/mRGO containing the same graphene content compared with the neat PCL, were prepared under melt conditions. The morphology and contact angle measurements for the prepared films were demonstrated. The impact of incorporated RGO and mRGO on the thermal and mechanical properties of the PCL matrix was studied. The results emphasized no change in thermal stability of the polymer composites after incorporation of the fillers while the films exhibited an improvement in the strength, the stiffness and ductility. Investigation of water sorption kinetics showed decreasing in the diffusion coefficient for all films reinforced with the nanofillers. Moreover, gas and water permeability displayed improvement in the barrier properties. Antimicrobial activity investigations revealed that films reinforced with mRGO exhibited high bactericidal activity against gram-positive bacteria compared with the neat PCL and those containing RGO. Moreover, incorporation of the prepared nanofillers showed a significant enhancement of the biodegradability of PCL polymer.