In the present study, redox-initiated free radical induced graft-copolymerization of microcrystalline cellulose (MCC) and methyl methacrylate (MMA) in aqueous solution has been carried out to develop a novel cellulose based copolymer. Cerium ammonium nitrate (CAN) was used as the initiator in the presence of nitric acid. Effects of monomer concentration, initiator concentration, polymerization time, and polymerization temperature on the grafting parameters of copolymers were studied. The successful grafting copolymerization between MCC and MMA was validated through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). In comparison to native MCC, the resultant copolymers exhibited better thermal stability and better compatibility to natural rubber, suggesting its potential application as reinforcement material in natural rubber.