High-performance lead-free piezoelectric ceramics with knockdown strain hysteresis are key components of high-precision actuators. However, high strain hysteresis in BaTiO₃-based ceramics results in stability degradation, lifespan reduction, and inferior positioning accuracy. Therefore, in this work, a (1−x)Ba(Sn_0.11Ti_0.89)O₃–xSrTiO₃–0.6 wt% MnO₂ (BST–xST) composition is elaborately designed to reduce strain hysteresis. Ultralow strain hysteresis (4.8%) is achieved by adjusting the phase structure and domain configuration. The transmission electron microscopy (TEM) results revealed that the composition consists of a rhombohedral–orthorhombic–tetragonal–cubic (R–O–T–C) four-phase, nanodomains, and active polar nanoregions (PNRs). Moreover, the piezoresponse force microscopy (PFM) results revealed that these active PNRs can respond quickly to applied electric field stimuli. These findings provide a feasible path to prepare piezoelectric compositions with ultralow strain hysteresis.