We describe the fabrication of a well-defined carbon nanotubes (CNTs)-based composite, in which the CNTs are individually wrapped by a polymer in homogeneous fashion and platinum nanoparticles (Pt) are immobilized on the polymer-wrapped CNTs. Polybenzimidazoles (PBIs) are used for the wrapping polymer since a strong adsorption of PBIs onto the CNT surfaces enables the exfoliation of CNT bundles and nanometer-thick PBI wrapping layer serves as a glue for the efficient immobilization of Pt. We demonstrate the use of the composite for the polymer electrolyte fuel cell (PEFC) electrocatalyst after acid doping. Single cell tests reveal that the ultra-thin PBI-wrapping layer around the CNTs serves as a proton conducting layer to deliver protons in the catalyst membrane. PEFCs using the composite show an excellent fuel cell performance at 120 °C under non-humid atmosphere, whereas the conventional Nafion-based PEFCs are not workable in such condition. Durability of the electrocatalyst was studied.