<p>Perovskite-structured materials have emerged as highly versatile catalysts for molecular transformations owing to their tunable electronic structures, compositional flexibility, and structural robustness. However, their catalytic performance is increasingly recognized to be governed not by static active sites, but by the dynamic evolution of surface states under reaction conditions. In this review, we provide a comprehensive and critical analysis of dynamic active site evolution in perovskite oxides, with a particular focus on how cation substitution, defect chemistry, and surface reconstruction collectively determine catalytic behavior at the molecular level. We systematically examine the interplay between lattice dynamics, electronic structure, and surface transformations, and their impact on reaction pathways in key processes including oxidation, reduction, and photocatalysis. By integrating recent experimental observations with theoretical insights, we establish unified structure–activity relationships that link lattice distortions, oxygen vacancy dynamics, and electronic conductivity to catalytic activity, selectivity, and stability. Importantly, we highlight the limitations of conventional static models and propose a dynamic mechanistic perspective that better captures the adaptive nature of perovskite catalysts under operando conditions. Finally, we identify critical challenges in correlating transient surface states with catalytic performance and outline emerging strategies for the rational design of next-generation perovskite catalysts. This work provides a conceptual framework for understanding and engineering dynamic active sites, offering new directions for advancing perovskite-based systems in energy conversion and sustainable chemical synthesis.</p>