To ensure the structural integrity of underground stations constructed prior to the implementation of seismic design codes, effective retrofitting is essential. Although aramid fiber-reinforced polymer (FRP) sheets are widely favored for their cost-effectiveness and ease of installation, their vulnerability to elevated temperatures limits their application in underground environments where fire risks are elevated. This study evaluates the multi-hazard resilience of reinforced concrete (RC) columns retrofitted with flame-retardant (FR) aramid sheets, focusing on both seismic performance and fire resistance through experimental and numerical approaches. Quasi-static cyclic tests were conducted on RC column specimens representing non-seismic and FR-aramid-retrofitted designs, and the results were evaluated using performance-based seismic design in accordance with FEMA 440. The unretrofitted column satisfied the target performance at the design basis earthquake (DBE) level but failed to achieve the collapse prevention objective under the maximum considered earthquake (MCE) level, whereas the FR-aramid-retrofitted specimen achieved the required performance objectives under both seismic hazard levels. Furthermore, a Bow-Tie analysis was performed to assess combined earthquake-fire hazards and was integrated with temperature-dependent axial force-bending moment (P-M) interaction curves. The findings indicate that FR-aramid retrofits maintain a larger residual strength envelope than unretrofitted columns at temperatures exceeding 400°C. These results indicate that FR-aramid sheets can be an effective retrofit option for enhancing the seismic and fire resilience of underground RC structures.