Nickel (Ni) exsolution from perovskite oxide lattices has emerged as a highly effective strategy to develop active, stable, and coking-resistant anodes for protonic ceramic fuel cells (PCFCs). Conventional Ni-based anodes, although widely employed due to their excellent catalytic activity toward the hydrogen oxidation reaction (HOR), suffer from several critical challenges under typical operating conditions. These include severe degradation caused by Ni particle agglomeration, delamination from the ceramic backbone, and carbon deposition when exposed to hydrocarbon fuels. Such structural and chemical instabilities significantly limit the long-term durability and performance of PCFCs. To address these limitations, the present study explores the in situ exsolution of Ni nanoparticles from doped perovskite oxide anodes as a means to achieve strong metal–support interaction and enhanced catalytic robustness. During controlled reduction, Ni cations migrate from the perovskite lattice to the surface, nucleating as uniformly distributed nanoscale particles that are partially embedded, or “socketed,” into the oxide framework. This anchored configuration ensures excellent thermal and mechanical stability, preventing particle coarsening and detachment even under prolonged operation. The resulting exsolved Ni–oxide interface provides abundant active sites for electrochemical reactions and facilitates rapid charge and proton transfer at the electrode–electrolyte boundary. In this work, the exsolution behavior of Ni from doped perovskite anodes was systematically investigated under various reduction temperatures and atmospheres to tune nanoparticle size, distribution, and density. Comprehensive structural and microstructural characterizations using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), and X-ray photoelectron spectroscopy (XPS) confirmed the formation of finely dispersed, metallic Ni nanoparticles anchored firmly to the perovskite surface. Electrochemical analyses, including current–voltage (I–V) characteristics and electrochemical impedance spectroscopy (EIS), demonstrated that the Ni-exsolved anodes exhibited substantially lower polarization resistance and higher peak power density than their conventional Ni-impregnated counterparts. The enhanced electrochemical performance is attributed to the synergistic effect between the exsolved Ni nanoparticles and the perovskite lattice, which collectively promote efficient HOR kinetics, proton conduction, and electronic transport. Moreover, redox cycling experiments revealed remarkable reversibility of the exsolution process, with Ni nanoparticles re-dissolving and re-exsolving without loss of performance or structural integrity. This self-regenerative capability contributes to long-term operational stability and resistance to fuel impurities, such as carbonaceous species, thereby mitigating coking and degradation. Overall, this study highlights Ni exsolution as a transformative approach for the rational design of advanced PCFC anodes that combine high catalytic activity, structural resilience, and long-term stability. The findings provide fundamental insights into the relationship between exsolution chemistry, microstructural evolution, and electrochemical functionality. By leveraging the unique properties of exsolved metal–oxide interfaces, this work contributes to the development of next-generation, high-efficiency, and sustainable PCFC systems for clean energy conversion and storage applications.