He joined the navy in 1942 and after World War Two studied electrical engineering at the United States Naval Academy.
Morris served in the Korean War before joining the CIA in 1956, for whom he carried out anti-espionage duties in Berlin, Paris, Kinshasa and Vietnam.
In 1965 he published The Washing of the Spears, a history of the 1879 Anglo-Zulu War, a book he had worked on mainly during a five-year posting in Berlin.
[4] Morris joined the Central Intelligence Agency in 1956, though he remained in the United States Navy Reserve, retiring as a lieutenant commander in 1972.
[2] In 1955 Morris met the author Ernest Hemingway in Cuba, the chance encounter gave him the idea of writing a history of the 1879 Anglo-Zulu War.
The historian Ian Knight regards the publication of The Washing of the Spears as marking the modern era of the study of the Anglo-Zulu War.
[4][3] In 1989, he founded the Trident Syndicate which published its own foreign affairs periodical, the Donald R. Morris Newsletter, until 2002.