Enhancing key parameters such as the piezoelectric coefficient (d₃₃), Curie temperature (T_C), electromechanical coupling coefficient (k_p), and dielectric loss (tanδ) is crucial for improving the overall performance of piezoelectric ceramics. However, the trade-off relationships among these parameters represent a significant challenge in this field. To address this issue, we propose a synergistic strategy that leverages atomic radius differences (Mg²⁺ and Pb(Mg_1/3Nb_2/3)O₃) to induce lattice distortion and promote ferroelectric domain growth. This approach successfully achieves the simultaneous enhancement of multiple parameters in the Pb(Ni_1/3Nb_2/3)O₃–PbZrO₃–PbTiO₃ system, resulting in excellent overall performance with d₃₃ = 681 pC/N, inverse piezoelectric coefficient d₃₃* = 953 pm/V, T_C = 213 °C, k_p = 0.69, and tanδ = 1.47%. Rietveld refinement, Rayleigh analysis, and piezoresponse force microscopy (PFM) characterization confirm that the cooperative modulation of lattice distortion and domain growth is key to performance improvement. Additionally, the material demonstrates excellent thermal stability and high-temperature dielectric breakdown strength. This study provides a simple and effective strategy to overcome the antagonistic relationships among multiple parameters in piezoelectric ceramics.