Magnetic nanoparticles (MNPs) have limited surface area which is a major drawback in the Fenton-based degradation of phenolic compounds, often resulting in reduced adsorption and degradation rates. Consequently, enhancing the surface area could potentially improve the adsorption rate, thereby, improving the degradation efficiency. In this context, the present study aims in the surface engineering of magnetic nanoparticles by coating them with chitosan. The structural and functional properties of the synthesized nanoparticles were examined, which validated the increased surface area and the presence of functional groups essential for adsorption and catalytic activity. The effectiveness of chitosan-coated MNPs (cMNPs) in the degradation of phenolic compounds was systematically investigated and key parameters (pH, particle to hydrogen peroxide ratio, and reaction time) were optimised using response surface methodology (RSM). Under the optimized conditions, a maximum degradation efficiency of 95% was achieved, which was approximately 0.5-fold higher compared to MNPs. The enhanced degradation is attributed to the increased surface area, which facilitated greater adsorption of phenolic compounds and improved the catalytic efficiency of the fenton process. Further, the synthesized MNPs could be easily recovered, which allowed easy reusability. Thus, this study established cMNPs as a promising and sustainable catalyst for the effective removal of contaminants from wastewater, providing a viable solution for environmental remediation applications.