Wiktionary
media maven
n. 1 A maven who has knowledge about how the media operate. 2 By extension, a person who has the power to promote a media project or person so as to enable a book to be published, a movie to be filmed, an actor to get a specific role, etc.
Usage examples of "media maven".
Well, I have pretty good information of my own that the late media maven Gus Gustafferson was one of CIOs agents.