An apparatus, method and computer program product for actively controlling the luminance (brightness) of illumination of a backlight of a mobile terminal according to the surrounding environment and a mobile terminal implementing such apparatus are disclosed. The mobile terminal includes: an illuminance sensor that detects ambient illuminance; a backlight controller that controls a brightness of backlight illumination by regulating the power outputted to the backlight according to a change in the ambient illuminance detected by the illuminance sensor; and a controller that monitors an operation state of the backlight controller or changes a set value of a particular register or component by cooperating with the backlight controller.