The stabilization of line of sight (LOS) against vehicle-induced disturbance is an essential feature of an electromechanical gimbaled sighting system with an optical sensor for sighting. We describe the design of a high-performance controller for an electromechancial target-tracking system with an optical sensor for sighting. The control law is obtained using a linear model of the electromechanical system. The modeling of the system is carried out using the experimental frequency response data. The H∞ control methodology is used to design a high-performance controller so as to control the rate of the line of sight. The mixed sensitivity optimization problem is posed and weighting functions are selected so that they not only encapsulate all the design goals but also accommodate the modeling uncertainties. A stabilizing controller with excellent robustness properties is obtained.