We report on the performance of thin-film yttria-stabilized zirconia (YSZ) synthesized by atomic layer deposition (ALD) at temperatures of 50–525 °C. Electrochemical impedance spectroscopy (EIS) was used for conductivity measurements. Relatively high conductivity values were observed in the low-temperature region when compared to reference values of YSZ synthesized by other methods. To investigate the conduction mechanism, various experimental variables were modified during the electrical measurements, including the ratio of yttria to zirconia in the ALD YSZ films and the atmospheric conditions. To relate the electrical properties to the structural characteristics, the crystallinity and microstructure were investigated using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Finally, the suitability of an ALD YSZ membrane as the electrolyte of micro solid oxide fuel cells was evaluated. An open circuit voltage of almost 1 V and decent power output were successfully measured below 100 °C.