[3] Heath was a White House correspondent for United Press International from February 1916 to August 1917 and then again from October 1919 to September 1920.
Then from 1941 to 1944, he was a consul in Santiago, Chile followed by less than a year as the chief of the Division of North and West Coast Affairs at the State Department.
Ambassador to the newly independent countries in Indochina including Laos (1950–1954), Cambodia (1950–1954), and South Vietnam (1950–1954).
Heath supported the Domino Theory and wrote that if the French pulled out "Only the blind could doubt the immediate Communist engulfment of Southeast Asia.
"[5][6] In October 1954 Heath and Lieutenant General John W. "Iron Mike" O'Daniel were authorized to begin a crash program to improve "the loyalty and effectiveness of the Free Vietnamese Forces."
The result was a formal agreement in December between representatives of France, the Republic of Vietnam, and the United States to supply direct aid through the Military Assistance Program (MAP).
Donald R. Heath Jr. had been a WWII courier working with the American spy Mildred Harnack, a great-great aunt of Rebecca Donner.