Michael Seto/Business Insider
The CBS Board of Directors elected Moonves to the position with a unanimous vote.
Redstone, 92 and in declining health, has been named Chairman Emeritus, CBS Corporation.
Shari E. Redstone, Sumner Redstone's daughter, will continue to serve as vice chair of the CBS Board, a position she has held since 2005.
"I am honored to accept the chairmanship of this great company," Moonves said in a statement.
"I want to thank Sumner for his guidance and strong support over all these years," he continued. "It has meant the world to me. I am particularly grateful that Shari Redstone has agreed to continue in her role as vice chair of the company. Her business acumen and knowledge of the media space remain very important to me as we move forward, and I greatly appreciate her support and invaluable counsel. I would also like to thank our excellent board of directors, who have contributed so significantly to our success. The people of CBS have achieved much together and I believe the best is yet to come."
Thomson Reuters
Meanwhile, Redstone served as chairman of the board of both CBS Corporation and Viacom, which he assumed after the separation of Viacom into two publicly traded companies in January 2006.
Redstone is the controlling shareholder of both companies.
As for the future of Redstone at Viacom, which he also chairs, reports say the Viacom board expects to replace him as chair as well.
Viacom board to meet tomorrow to elect Redstone's replacement as Chairman-sources.Regardless, he's still the controlling shareholder.$VIAB