 He served as president of National Amusements, the Redstone family business through which they exercise various degrees of control in Viacom and CBS, from 1987 until 1994, two years after the divorce, served as Executive Vice President and on the Board of Directors of Viacom, and remained a consultant to Mr. Redstone and his company until 2009.He has served as an advisor and consultant in both public and private international relations, assisting numerous governments (including the United States, the U.K., Austria, Thailand, China, Jordan and others) in matters of diplomacy and international relations, and he has advised numerous national and multi-national business ventures in the United States and abroad.Korff is the author of "Meshivas Nefesh Yitzchok