<p>This study rigorously evaluates lead rubber bearing (LRB) performance for seismic isolation of an RC structure featuring integrated shear walls. Advanced dynamic time-history analyses to systematically identify the optimum effective damping ratio of lead rubber bearings for a uniquely challenging structural system, one that is exceptionally stiff and stable at the superstructure level yet highly flexible at the base level, thereby providing a robust framework for tailoring isolator design to achieve simultaneous control of isolator and superstructure responses. A symmetric building incorporating special RC shear walls was designed, and a critical frame was subsequently extracted and analyzed as a separate nonlinear system in SeismoStruct. Seven LRB configurations with varied effective damping ratios were installed at the base, and the structure was excited using far- and near-fault earthquake records. Results indicate that under far-field excitations, isolator-induced shear and base shear are minimized at approximately 5% damping, axial forces are lowest at 2%, and isolator displacement is best controlled at 10%, with inter-story drift and story-level absolute accelerations minimized at 2%. In contrast, near-fault excitations require a damping ratio near 50% to reduce isolator forces, accelerations, inter-story drift, and base shear, with displacement control optimized at 30%. These findings underscore the necessity of hazard-specific tuning of LRB parameters, providing novel insights for enhanced seismic isolation design.</p>