Mark Malloch Brown is a British diplomat. He has served as Deputy Secretary-General of the United Nations since April, 2006.
Before his current appointment, he was the Secretary-General’s Chef de Cabinet since January 2005. In that position, he worked closely with the Secretary-General and the Deputy-Secretary General on all aspects of U.N. work, including setting an ambitious reform agenda for the United Nations, much of which was endorsed by world leaders at the World Summit in New York last September.
Prior to becoming Chef de Cabinet, Malloch Brown served as Administrator of the United Nations Development Program (UNDP), the U.N.’s global development network, from July 1999 to August 2005. During that time, he was also the Chair of the United Nations Development Group.
Source - http://www.un.org/News/ossg/sg/stories/dsgbio.asp