Aging and fatigue are the two main concerns regarding the performance reliability of piezoelectric ceramics. Compared with fatigue, less efforts have been made towards clarifying the micromechanisms of aging. In this report, we employ electric field in-situ transmission electron microscopy (TEM) to directly visualize the domain structure evolution during fatigue and the subsequent aging process in the 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BZT–BCT) polycrystalline ceramic. The macroscopic aging behaviors, including the development of internal bias field (Ebias) and the degradation in switchable polarization (2Pr), are correlated with the microscopic domain wall clamping and domain disruption resulted from the redistribution of oxygen vacancies driven by depolarization field.