Kemény graduated in 1978 as veterinary doctor. In 1990 he received the degree of water polo trainer, and in 1998 the water polo master trainer. As a player, he was member of the European Junior Champion team in Duisburg 1973. Under his leadership the Hungarian National team became one of the most successful teams in the world winning the Olympic Games in 2000 and 2004 and 2008, the Water Polo World Championship in 2003, the FINA Water Polo World League in 2003 and 2004, the FINA Water Polo World Cup in 1999, and the Water Polo European Championship in 1997 and 1999.