According to various embodiments, an electronic device includes a housing, a display viewable through a front surface of the housing and configured to display a screen, a camera sensor disposed in at least a portion of the front surface of the housing and configured to measure an external illuminance, a processor operationally connected to the display and the camera sensor; and a memory operationally connected to the processor. The memory may store instructions that, when executed, cause the processor to control the electronic device to: detect an turn-on event of the display, turn on the camera sensor to acquire the external illuminance using the camera sensor based on the display being turned on, acquire preview image information for a specified time through the camera sensor, turn off the camera sensor, acquire the external illuminance using an exposure time and a brightness value based on the acquired preview image information, and control a luminance of the display based on the external illuminance.