Ordered hierarchical nanostructured carbon (OHNC) has been fabricated through inverse replication of silica template and explored for the first time to support high loading of Pt nanoparticles as cathode catalyst in proton exchange membrane fuel cells (PEMFC). The superb characteristics such as ordered hierarchical nanostructure, large surface area, and mesopore volume enable the OHNC to support high loading (60 wt %) of Pt nanoparticles with uniform dispersion and small particle size. Compared to carbon black Vulcan XC-72 (VC)-supported Pt (60 wt %), the OHNC-supported one has exhibited greatly enhanced catalytic activity toward oxygen reduction reaction by ca. 53−88% and considerably improved PEMFC performance. More importantly, unlike the VC-supported Pt catalysts, the OHNC-supported Pt (40 or 60 wt %) outperforms the OHNC-supported Pt (20 wt %) even at a low catalyst loading of 0.2 mg Pt/cm2 in the cathode, which represents a significant breakthrough in fuel cell technology because of the expectable marked reduction in fabricating cost of the supported Pt catalyst and the corresponding system weight and considerably improved fuel cell performance.