The main objective of this research is to develop a hybrid damper by combining the friction damper (FD) and the X-shaped metallic damper (XMD) to enhance the performance of a building under seismic excitations with different peak ground accelerations (PGA). Four- and twelve-storey-reinforced concrete buildings were retrofitted with the hybrid damper, and seismic fragility, nonlinear dynamic, and life cycle cost analyses were executed on both structures to evaluate the performance of the hybrid damper and are compared with the FD and XMD of same yield load. According to the nonlinear dynamic analysis results, when a four-storey structure is installed with the XMD, FD, and hybrid dampers, the percentage of deduction of the average of the maximum interstorey drifts is 63, 67, and 74, respectively. When a twelve-storey structure is installed with the XMD, FD, and hybrid dampers, the percentage of deduction of the average of the maximum interstorey drifts is 59, 64, and 71, respectively. So the performance of the hybrid damper is superior to the XMD and FD in reducing interstorey drift of both structures. Results also show that the hybrid damper has enhanced the energy dissipation capacity compared to the XMD and FD under earthquakes with both low and high PGA values. According to fragility analysis results, the performance of the hybrid damper is superior to the XMD and FD in reducing the probability of attaining the collapse state. Life cycle cost analysis results show that structures with the hybrid damper acquired the shortest repair time and lowest repair cost.