He was Permanent Secretary of SELA from April 2008 to January 2013. Previously, from 1988 to 1993, he worked in the organization as Deputy Director of Economic Relations, as well as a Special Adviser.
From 2005 to 2008 he was Undersecretary of the Latin American Association for Integration (ALADI), based in Montevideo, Uruguay.
From 2002 to 2005, he held the post of Director of the Programme on Globalization, Liberalization and Sustainable Human Development (UNDP- UNCTAD). Previously, he worked as Inter-regional Adviser to UNCTAD in Geneva, Switzerland. At present, Ambassador Rivera is an International Adviser