Randolph Marcus taught secondary school students in Asella, Ethiopia from 1966 to 1968. He joined the Foreign Service in 1969. He began his State Department career as a USAID civilian advisor in South Vietnam. Later postings included economic and political work at US Embassies in Togo, Brazil, Mexico, and Argentina, In Washington, he served as an economic affairs delegate with the US Mission to the Organization of American States and an advisor on Latin America in the Office of Counterterrorism. Following his retirement from the Foreign Service, Mr. Marcus worked for the Air Force Office of Special Investigations and the Defense Intelligence Agency as a counterterrorism analyst. He also spent a year as a Red Cross volunteer at the Walter Reed National Military Medical Center in Bethesda.