Na1/2Bi1/2TiO3‐based materials have been earmarked for one of the first large‐volume applications of lead‐free piezoceramics in high‐power ultrasonics. Zn2+‐doping is demonstrated as a viable route to enhance the thermal depolarization temperature and electromechanically harden (1‐y)Na1/2Bi1/2TiO3‐yBaTiO3 (NBT100yBT) with a maximum achievable operating temperature of 150 °C and mechanical quality factor of 627 for 1 mole % Zn2+‐doped NBT6BT. Although quenching from sintering temperatures has been recently touted to enhance TF‐R, with quenching the doped compositions featuring an additional increase in TF‐R by 17 °C, it exhibits negligible effect on the electromechanical properties. The effect is rationalized considering the missing influence on conductivity and therefore, negligible changes in the defect chemistry upon quenching. High‐resolution diffraction indicates that Zn2+‐doped samples favor the tetragonal phase with enhanced lattice distortion, further corroborated by 23Na Nuclear Magnetic Resonance investigations. Zn2+‐doping (0.5 and 1 mole %) is demonstrated to enhance the thermal depolarization temperature (Td) and electromechanically harden (1‐y)Na1/2Bi1/2TiO3‐yBaTiO3 (NBT100yBT). Quenching (Q1100) the doped compositions feature an additional increase in Td by ~15‐20 °C. The results are rationalized based on the stabilization of ferroelectric order, evidenced from the enhanced tetragonality and rhombohedral (R) distortion, changing phase fraction (using high resolution diffraction) and decrease in the cubic phase fraction (using NMR) upon Zn2+‐doping.