Abstract High mechanical quality factors (QₘB ≈ 1400), determined from the antiresonance frequency, together with a large piezoelectric coefficient (d₃₃ = 1450 pC/N) and voltage coefficient (g₃₃ = 48 mV·m/N), were obtained for Mn-doped Pb(In₁/₂Nb₁/₂)O₃–Pb(Mg₁/₃Nb₂/₃)O₃–PbTiO₃ (PIN–PMN–PT) single-crystal bar resonators (4 × 4 × 12 mm³) using a low-stress electrically shielded fixture. The [001]c-oriented crystals were grown by a continuous-feeding Bridgman (CF-BM) method, enabling the production of large (D80 × L120 mm, ≈ 5 kg) crystals with excellent composition and piezoelectric property uniformity. To the best of the authors’ knowledge, no previously reported piezoelectric material has simultaneously exhibited d₃₃ > 1400 pC/N, g₃₃ > 45 mV·m/N, and Qₘ > 1400 together with kilogram-scale crystal uniformity. These Mn-doped PIN–PMN–PT single crystals grown by CF-BM process are promising candidates for high-power, high-reliability medical ultrasonic and underwater acoustic devices.