Ian McNeill, soldier and military historian, was born in Melbourne on 12 June 1933 but grew up and was educated in Wagga Wagga, New South Wales. In 1950, at the age of 17, McNeill entered the Royal Military College, Duntroon and, showing early signs of his later vocation as a writer, topped his class in English over each of his three years there. A keen outdoorsman, he also joined the college's snow skiing club.

McNeill graduated in 1954 and the following year was posted as a rifle platoon commander to the 1st Battalion, Royal Australian Regiment (1RAR) then serving in Korea. Shortly after returning, McNeill published his first piece army life had not dimmed his enthusiasm for writing. In 1957 he became a founding member of 1 Special Air Service Company as a platoon commander and served with the company until 1961 when he joined the headquarters of the Australian Army Force in Singapore. He visited South Vietnam for a brief inspection tour in November 1962.

In 1965 he was selected to join the Australian Army Training Team Vietnam (AATTV) and served a one-year tour of duty as Senior Australian Adviser in the northern I Corps region of South Vietnam from August 1965 to August 1966. He developed a genuine affection for the Vietnamese people and their culture during his service there and the experience was the beginning of a life-long association with that country.

McNeill returned to Australia and attended the Staff College at Queenscliff in Victoria before going on to serve in the 1st, 3rd and 5th Battalions of the Royal Australian Regiment. In 1971, while still a soldier, he participated in the final anti-war Moratorium march. McNeill had come to believe that the government was following a flawed strategy and that Australian soldiers were dying needlessly in Vietnam while the government prevaricated about bringing them home.

In 1972 he joined the Military History Cell at Army Headquarters in Canberra where he conducted historical research, wrote, and interviewed army commanders about their Vietnam experiences. He also undertook part-time study, gaining a Master of Arts degree and proving himself to be an excellent scholar. During this period, McNeill wrote The team, a history of the unit with which he had served in Vietnam. He left the Army as a major in 1982 and joined the Australian War Memorial's Official History Unit in 1984. There he researched and wrote the first official history volume on ground operations in Vietnam, To Long Tan. Published in 1993 this outstanding piece of historical work earned McNeill the Templer Medal, the Commonwealth's most prestigious award for military history writing.

McNeill went on to write a number of further articles and book chapters on the Vietnam War. His skill in writing battle pieces is most evident in his chapter on the battle of Long Tan in To Long Tan, now recognised as a model of the genre. In 1997 he was awarded a Doctorate of Letters for The team and To Long Tan from the University of New England, an achievement of which he was particularly proud. McNeill had not long before undergone vascular surgery but had returned to work in the Official History Unit. Just a year after receiving his doctorate, on 3 October 1998, McNeill suffered a fatal heart attack and died in Canberra Hospital. At the time of his death he was working on the successor volume to To Long Tan, which was published as two volumes completed by his co-author Ashley Ekins, On the offensive (published in 2003) and Fighting to the finish (published in 2012).