[3] From 1979 to 1983, Almaguer served as Deputy Mission Director for the United States Agency for International Development (USAID) in Panama.
During the 1990-91 academic year, Almaguer participated in the U.S. State Department's Senior Seminar Program overseen by the U.S. Foreign Service Institute.
[5] Almaguer retired from the United States Foreign Service with the personal rank of Career Minister in November 2002.
From 2003 to 2005, Almaguer served as a Senior Adviser to the Pan American Development Foundation, was a United States Delegate to the 60th annual meeting of the United Nations Commission on Human Rights, and worked as an international consultant on economic and social development reforms.
Almaguer was appointed as Secretary for Administration and Finance at the Organization of American States, the third-ranking position at the OAS, in February 2005, where he served for almost six years.