High-performance platinum (Pt)-based catalyst development is crucially important for reducing high overpotential of sluggish oxygen reduction reaction (ORR) at Pt-based electrocatalysts, although the high cost and scarcity in nature of Pt are profoundly hampering the practical use of it in fuel cells. Thus, the enhancing activity of Pt-based electrocatalysts with minimal Pt-loading through alloy, core−shell or composite making has been implemented. This article deals with enhancing electrocatalytic activity on ORR of commercially available platinum/carbon (Pt/C) with graphene sheets through a simple composite making. The Pt/C with graphene sheets composite materials (denoted as Pt/Cx:G10−x) have been characterized by several instrumental measurements. It shows that the Pt nanoparticles (NPs) from the Pt/C have been transferred towards the π-conjugated systems of the graphene sheets with better monolayer dispersion. The optimized Pt/C8:G2 composite has higher specific surface area and better degree of graphitization with better dispersion of NPs. As a result, it shows not only stable electrochemical surface area but also enhanced ORR catalytic activity in respect to the onset potential, mass activity and electron transfer kinetics. As shown by the ORR, the Pt/C8:G2 composite is also better resistive to the alcohol crossover effect and more durable than the Pt/C.