A cross-linked poly(vinyl alcohol) (PVA)/poly(acrylic acid) (PAA) fibrous web supported composite ionomer (Aquivion) membrane was fabricated and evaluated for high-temperature and low-humidity proton exchange membrane fuel cell operations. PVA/PAA fibrous webs were initially prepared by the electrospinning method, followed by heat-treatment for cross-linking the polymers in order to increase mechanical strength. The successful formation of cross-linking bonds between PVA and PAA was confirmed by Fourier transform infrared spectroscopy analysis. For electrolyte membrane preparation in single cell tests, the fibrous webs were further impregnated with an Aquivion ionomer phase, which could be observed in scanning electron microscopy images. The prepared composite membrane had considerably improved mechanical strength compared to Aquivion-only membranes, as was evident by a 1.78-fold increase in tensile strength. Single cell and proton conductivity tests were also performed. The Aquivion-impregnated PVA/PAA fibrous composite membranes showed approximately 1.4-, 1.6-, and 1.2-fold higher maximum power densities than did the Aquivion-only membranes at 75°C/100% relative humidity (RH), 75°C/40% RH, and 120°C/40% RH, respectively. These results demonstrate the strong potential of the cross-linked PVA/PAA fibrous composite membranes impregnated with Aquivion for application to PEMFC operation at high temperatures and in low-humidity (>40% RH) regions.