Two-step sintering (TSS) in a reducing atmosphere has been employed to obtain fine-grain BaTiO3 ceramics with a core-shell microstructure, a more uniform grain-size distribution, and superior reliability for multilayer ceramic capacitor applications. Compared to ceramics of the same composition conventionally sintered for about the same time, TSS ceramics feature a thinner shell thickness thus a stronger dopant localization, which leads to a lower VO.. concentration, higher internal resistance and more dopant-VO.. association. Improved reliability is manifest in a 50% higher breakdown strength at ambient temperature and a 400% longer endurance time to withstand DC stress at 185 degrees C, in addition to a less field-and-temperature-dependent capacitance. A scaling analysis of the VO.. redistribution and endurance dynamics identifies VO.. transmission across the shell-grain-boundary region as the critical element beneficially impacted by core-shell structure and two-step sintering.