In this work, Nafion ionomer was prepared by a dissolution method in high pressure-temperature autoclave reactor using Nafion membrane sources. Zirconia nanoparticles were synthesized by the microwave assisted gel combustion method. The synthesized nanoparticles were characterized by XRD and FESEM, and then added to the Nafion solution to prepare recast Nafion nanocomposite membranes (R-Nafion/ZrO2) with different loading of ZrO2 nanoparticles. Membranes were prepared by recasting method and characterized in terms of water uptake, dimensional stability, ionic conductivity, chemical stability (Fenton test), tensile strength, and scanning electron microscope (SEM) techniques. The obtained results for nanocomposite membranes were compared to the filler-free recast Nafion and commercial Nafion membranes. The nanocomposite membranes showed higher water uptake, mechanical and oxidative stabilities and the hygroscopic zirconia nanoparticles resulted higher proton conductivity of nanocomposite membranes at different temperatures in comparison with pure recast Nafion membrane. The prepared membranes showed defect free, dense microstructure, and good dispersion of nanoparticles in the membranes’ matrix. The results illustrated the prepared nanocomposite membranes have good physicochemical and electrochemical properties for PEMFC applications.