In this study, the position control of a closed-loop pump-controlled hydraulic servo system is investigated in the presence of uncertainties arising from system wear. To this end, a nonlinear backstepping-based controller is designed, and the stability of the closed-loop system is guaranteed using Lyapunov stability analysis. In the controller design, the effects of internal leakage, friction, and variations in hydraulic parameters are considered as realistic system uncertainties. First, the hydraulic servo system under study is mathematically modeled based on its physical parameters. Then, the backstepping controller is developed by explicitly accounting for system uncertainties. To evaluate the performance of the proposed controller, an experimental test rig with dynamic behavior similar to that of an industrial hydraulic servo system is designed and implemented. The controller performance is experimentally assessed through real-time implementation using an Arduino DUE hardware platform and a sinusoidal reference input. Experimental results demonstrate that the proposed backstepping controller significantly reduces the tracking error compared to a genetic algorithm–optimized PID controller and effectively eliminates the steady-state error, which is approximately 3% in the PID-based approach. Specifically, the root mean square (RMS) tracking error achieved by the proposed method is reduced to less than one-quarter of that obtained using the PID controller. The results confirm the effectiveness and practical applicability of the proposed control strategy for industrial hydraulic servo systems.