Sulfonated branched polymer membranes have been gaining immense attention as the separator in energy-related applications especially in fuel cells and flow batteries. Utilization of this branched polymer membranes in direct methanol fuel cell (DMFC) is limited because of large free volume and high methanol permeation. In the present work, sulfonated fullerene is used to improve the methanol barrier property of the highly branched sulfonated poly(ether ether ketone sulfone)s membrane without sacrificing its high proton conductivity. The existence of sulfonated fullerene with larger size and the usage of small quantity in the branched polymer matrix effectively prevent the methanol transportation channel across the membrane. The composite membrane with an optimized loading of sulfonated fullerene displays the highest proton conductivity of 0.332 S cm(-1) at 80 degrees C. Radical scavenging property of the fullerene improves the oxidative stability of the composite membrane. Composite membrane exhibits the peak power density of 74.38 mW cm(-2) at 60 degrees C, which is 30% larger than the commercial Nafion 212 membrane (51.78 mW cm(-2)) at the same condition. From these results, it clearly depicts that sulfonated fullerene-incorporated branched polymer electrolyte membrane emerges as a promising candidate for DMFC applications.