A vehicular interior rearview mirror assembly includes a mirror head pivotable about a mirror support, which is configured to attach at an interior portion of a vehicle. The mirror head includes a mirror casing and a mirror reflective element having a transflective mirror reflector that at least partially reflects light incident thereon and at least partially transmits incident light therethrough. A video display device is disposed behind a reflective region of the mirror reflective element and includes a display screen backlit by a backlighting device, which includes a plurality of micro-LEDs disposed at electrically conductive traces of a flexible circuit element. With the mirror support attached at the interior portion of the vehicle, the video display device is operable to display video images captured by a camera of the vehicle, whereby light emitted by the video display device passes through the mirror reflective element for viewing displayed video images.