Column base regions are among the most critical parts of reinforced concrete (RC) frames, as they are highly susceptible to stress concentration, cracking, and plastic hinge formation under cyclic seismic loading. In this study, the seismic performance of RC frames strengthened at the column base using High-Performance Fiber-Reinforced Cementitious Composite (HPFRCC) plates reinforced with Glass Fiber-Reinforced Polymer (GFRP) bars was numerically investigated. To determine the optimal mixture for manufacturing the strengthening plates, the mechanical properties of several HPFRCC mixtures containing different percentages of wollastonite powder were evaluated, and the mixture with 20% cement replacement by wollastonite was selected as the optimum composition. After validation against experimental results, the numerical model of the RC frame was employed in a parametric study to investigate the effects of HPFRCC plate thickness and GFRP bar characteristics on the structural behavior. The results demonstrated that the proposed HPFRCC–GFRP strengthening system significantly enhanced both the load-carrying capacity and energy absorption of the frame, increasing the lateral load capacity by approximately 36% and the energy absorption capacity by about 40% compared with the reference specimen. However, the evaluation of the strengthening efficiency index revealed that configurations with thinner HPFRCC plates and smaller-diameter GFRP bars, despite exhibiting lower absolute capacities, provided considerably higher material efficiency. Overall, the findings indicate that HPFRCC plates reinforced with GFRP bars can serve as an effective strengthening technique for column base regions, leading to substantial improvements in the seismic performance of reinforced concrete frames subjected to cyclic loading.