Our recently developed fast infiltration technique enables loading of nanostructured catalyst into porous metal-supported solid oxide fuel cells in 30 minutes per cycle compared to a few hours in the standard slow infiltration process. This technique maintains the advantages of metal supported solid oxide fuel cells (MS-SOFC) such as rapid thermal cycling, mechanical ruggedness, and redox tolerance while developing more efficient and stable fuel cells and electrolyzers. The impact of process parameters such as heating rate, number of infiltration cycle, and firing temperature on the cell performance and stability will be discussed. The crystallite sizes of the catalysts fired at a temperature range of 400 to 900°C were calculated from X-ray diffraction patterns using the Scherrer equation, and compared to the particle size of the catalysts obtained from scanning electron microscopy images. The electrochemical performance of as-fabricated cells tested in hydrogen, reformate, and ethanol fuels under identical test conditions will be presented and related to the infiltration process conditions and resulting catalyst structure. For the Pr-oxide cathode and Ni (40)-SDC (60) anode catalysts, firing at low temperature (400 to 600°C) yields high initial performance but degrades quickly due to coarsening of the small nanoparticle catalysts. Optimal firing temperature and infiltration numbers, and pretest and posttest characterization of the MS-SOFC architecture and interfaces will be discussed. Phenomena of mass transportation, phase change, catalyst coarsening, and Cr poisoning on the catalysts will be diagnosed by real-time electrochemical impedance spectra, thermal gravimetric analysis, and scanning electron microscopy.