A hysteretic damper is a structural component designed to undergo cyclic plastic deformation in order to absorb energy to reduce damage to building structures. The primary objective of this study is to compare the performance of hysteretic dampers at room temperature with their performance under potential high-temperature conditions caused by post-earthquake fires. A geometric model of an effective steel hysteretic damper was developed and simulated in the ABAQUS software under cyclic loading conditions at both room temperature and simulated high-temperature fire conditions. The cyclic shear loading was applied to replicate earthquake wave frequencies. The simulation results were compared with published experimental results, thus validating the simulation model. The simulations indicate that, compared to room temperature, the energy dissipation capacity of the damper decreased by 24.4% under high-temperature conditions, and the effective stiffness decreased by 30.3%. The study highlights a significant reduction in the damping performance of the damper under high-temperature conditions. This factor may become a critical consideration in future research and design.