This paper reports novel results regarding the effects of electrospun carbon nanofibers (e-CNF) as a catalyst support by comparison with the commercial Vulcan XC-72R (denoted as XC-72R) as granular particles. The e-CNF was synthesized by stabilizing and carbonizing the electrospun PAN-based fibers. The e-CNF showed an average diameter of 250 nm with a rough surface and was partially aligned along the winding direction of the drum winder. The characteristic morphology was fundamentally dependant on the shape of the carbon materials. The average pore size of the e-CNF was 2.36 nm, while that of the XC-72R was 10.92 nm. The morphology of e-CNF was developed by shallow pores with rough surfaces due to the effects of electrospinning and carbonization, while that of the XC-72R was largely developed by mesopores rather than micropores due to the granular shape. Compared to XC-72R, the performance of the MEA prepared by e-CNF was excellent, owing to the morphology and the enhanced electrical conductivity. The Pt utilization of Pt/e-CNF was 69%, while that of Pt/XC-72R was 35%.