This study presents an intelligent control approach to enhance power quality in a grid-connected hybrid renewable energy system integrating solar photovoltaic and wind sources. Such systems are highly susceptible to environmental variations, particularly wind speed fluctuations, which can reduce operational efficiency and stability. In addition, disturbances including three-phase faults and voltage deviations at the point of common coupling (PCC) may negatively influence system performance and reliability. To overcome these challenges, a Static Synchronous Compensator (STATCOM) is employed to provide dynamic reactive power support, thereby strengthening renewable energy integration and improving voltage regulation. Owing to the nonlinear and complex characteristics of hybrid systems, an advanced multi-objective Grey Wolf Optimization (GWO) algorithm is adopted to optimally tune controller parameters, enhancing robustness and overall system reliability. Simulation analyses under diverse operating conditions demonstrate that the system maintains voltage and current levels close to 1 pu during swell and sag events, ensures effective reactive power compensation during high renewable penetration, improves power quality under unbalanced nonlinear load conditions, and sustains PCC voltage within the range of 0.93–0.98 pu during three-phase faults. The results confirm notable improvements in voltage profile, current waveform quality, and Total Harmonic Distortion (THD), along with faster dynamic response, thereby validating the effectiveness of the proposed GWO-based STATCOM control strategy for hybrid renewable energy applications.