Harland was born in Wellington in 1931, and attended Victoria University of Wellington, where he received an MA (First Class) in History under the guidance of New Zealand historian J.C. Beaglehole in 1955, and at the Fletcher School of Law and Diplomacy in Boston, where he received an AM.
Harland was a highly regarded strategic thinker, who rose quickly through the ranks in the Ministry of Foreign Affairs.
In 1973, Harland was appointed New Zealand's first Ambassador to China, where he was responsible for opening up diplomatic relations with that country.
Harland has written of the period that until then, New Zealand's best-known connection with China was Rewi Alley.
In 1976, Harland returned to New Zealand as Assistant Secretary of Foreign Affairs, before taking up the post of Permanent Representative to the United Nations in New York in 1982.