Cost reduction and long-term durability are crucial issues for the commercialization of polymer electrolyte membrane fuel cells. To accomplish these goals, herein, we report an electrospun iron and nitrogen codoped mesoporous carbon nanofiber (Fe-N-MCNF) for use as both a low-cost nonprecious metal catalyst and a durable support of platinum nanoparticles. Silica nanoparticles and polyvinyl acetate are used together as porogens to create mesopores. As a synergetic effect of these two types of porogens, numerous mesopores are successfully formed inside of the carbon nanofibers. The highly mesoporous structure increases the specific surface area and improves the diffusion kinetics of the reactants, leading to an increase in the effective surface area of the Fe-N-MCNFs for electrochemical reactions. Therefore, the Fe-N-MCNFs can have high oxygen reduction reaction activity alone in an acidic solution and the ability to provide a large surface area for platinum nanoparticles as a support. The platinum nanoparticles on the Fe-N-MCNFs are highly stable under an oxidative potential condition of fuel cells due to the high corrosion resistance of the graphitized carbon structure. This work demonstrates that Fe-N-MCNF can be utilized as both a low-cost catalyst and a durable support in practical fuel cell applications.