Systems and methods for implementing an online content item campaign with selective call functionality can include a processor determining a rendering frequency of instances of a third-party content item for rendering with a call icon, based on a resource of the third-party content provider. The processor can provide a first instance of the content item for rendering with the call icon in accordance with the rendering frequency of instances. A call bridge device can receive a call from the client computing device upon actuation of the call icon, direct the call to a phone number of the third-party content provider, and determine a parameter of the call. The processor can adjust the rendering frequency of instances based on the parameter of the call and provide instances of the content item for display by client computing devices with the call icon in accordance with the adjusted rendering frequency of instances.