A method is implemented on a server system for initiating by voice display of closed captions (CC) for media content. The server system receives a voice message recorded by an electronic device, and determines that the voice message is a first CC initiation request including a user voice command to initiate closed captions and a user voice designation of a display device playing the media content for which closed captions are to be activated. The server system identifies in a device registry a cast device associated in a user domain with the electronic device and coupled to the designated display device, and sends a second CC initiation request to the cast device, thereby enabling the cast device to execute a media play application that controls the designated display device to turn on and display the closed captions of media content currently displayed on the designated display device.