A seat assembly having an automatically adjustable head restraint is provided. A seat back is mounted within a vehicle and a head restraint assembly is adjustably mounted to the vehicle and disposed adjacent the seat back. The seat back includes a sensor mounted adjacent an upper portion of the seat back for detecting the presence and position of a passenger relative to the head restraint. A controller is in communication with the sensor and receives the output signal of the sensor. The controller then generates a control signal in order to position the head restraint based on the output signals of the sensor. An actuator is connected to the head restraint for positioning the head restraint based on a control signal received from the control module.