Sumner Murray Redstone was an American billionaire businessman and media magnate. He was the founder and chairman of the second incarnation of Viacom, chairman of CBS Corporation, and the majority owner and chairman of the National Amusements theater chain.

The second incarnation of Viacom Inc., was an American multinational mass media and entertainment conglomerate with interests primarily in film and television. It was established on December 31, 2005, as one of two companies which succeeded the original Viacom, alongside the second CBS Corporation. The controlling shareholder of both companies was National Amusements, a theater company headed by businessman Sumner Redstone. The split was structured so that the original Viacom changed its name to CBS Corporation and spun out its cable and film interests as a new Viacom.