In the automotive engineering, semi-active suspension (SAS) system has been one of the most attractive research projects. The SAS system usually refers to the damping force control using an adjustable damper. This research proposes a cuckoo search optimized proportional-integral-derivative (CS-PID) strategy for the damping force control system in order to improve the vehicle performance under different driving conditions and to improve the handling stability and smoothness of driving. Firstly, a quarter car dynamic model with an air spring and an adjustable damper is developed. Subsequently, the CS-PID controller is designed to generate the desired damping force according to the vehicle states in a real-time. Simulation results reveal that the vehicle performance can be greatly improved with the proposed controller.