Born in Dunedin, McIntyre commenced a journalism degree at the University of Otago but abandoned his studies and went to England in 1931 to attend the Slade School of Fine Art.

By 1940, he was serving in the Middle East with the 2nd New Zealand Division, where his artwork caught the attention of Major General Bernard Freyberg, the commander of the 2NZEF.

[2] He was educated at Otago Boys' High School[1] and, encouraged by his father,[2] received instruction in art from Alfred O'Keeffe, a local artist, executing several works for family and friends.

In April 1940, the unit left England for Egypt, where it was initially based at Maadi Camp, on the outskirts of Cairo, and attached to the 2nd New Zealand Division.

He provided drawings for Parade, a military magazine and was invited to prepare artwork to form the basis of a security poster.

[8] His skills soon saw him transferred to the draughting office at the headquarters of the 2nd New Zealand Division, preparing maps and drawings of Italian defensive positions based on aerial photographs.

His workspace was surrounded by some of his own artwork which soon attracted the attention of the division's commander, Major General Bernard Freyberg.

[11] In January 1941, Freyberg, tiring of the lengthy appointment process, selected McIntyre as the official New Zealand war artist, promoting him to lieutenant at the same time.

[13] When the 2nd New Zealand Division was sent to Greece, as one of a number of Allied units dispatched to support the country in early March 1941 in anticipation of an invasion by Germany,[14] McIntyre was ordered to remain in Egypt.

McIntyre was present during the airborne invasion of 20 May and it was at this time that he began to establish his methods for capturing events as they unfolded before him.

[1] From the fighting in Crete, McIntyre produced a number of notable works; landings of Fallschirmjäger (paratroopers), bombing of divisional field hospitals, and crashed German gliders.

[17] On returning to Egypt after the division had been evacuated from Crete at the end of May, several of McIntyre's works were published in Parade magazine.

When authorities announced the award of the Victoria Cross to Lieutenant Charles Upham of the 20th Battalion, McIntyre was instructed to undertake a portrait of him.

[23] After Operation Crusader, McIntyre returned to Egypt and spent time working up his sketches into completed paintings.

[25] In June 1942, the 2nd New Zealand Division was heavily engaged at Minqar Qaim, where it had been encircled by the Axis forces but successfully broke out.

[27] Following the withdrawal of the Axis forces into Libya and then Tunisia, the 2nd New Zealand Division, along with the rest of the British 8th Army, and McIntyre followed, painting along the way.

[28] With the war in Africa over following the surrender of the Axis forces there,[29] in July 1943 the first group of long serving soldiers of the 2NZEF were returning to New Zealand on furlough.

[32] McIntyre left for Egypt on 12 January, intending to go onto to Italy where the 2nd New Zealand Division was engaged in the Italian campaign.

[31] Some of his most notable war art was produced at this time, including depictions of the controversial bombing of the Cassino Monastery.

[34] He was in Rome shortly after the city's liberation by American forces, where at Freyberg's request he executed a portrait of Pope Pius XII.

[38] During this time, he visited Trieste, Florence, monasteries in Italy and Greece, returned to Crete, before receiving his discharge orders at the end of the year.

[39] Arriving in Dunedin in February 1946, McIntyre set up a studio on the city's Princes Street and started working full-time on commissioned portraits and landscapes.

In return, many established local artists, such as Toss Woollaston and Colin McCahon who were both pacifists, decried the fact that McIntyre's reputation was based on his war art.

[49] Named for the small town of Kākahi in the King Country where he owned a holiday home,[50] the book highlighted themes of conservation and rural landscapes.

After initially claiming it lacked hanging space for them, it set about centralising the war artist's work to the National Archives.

Earlier in the year, Wellington City Gallery held an exhibition of his war art; over 22,000 people had viewed his work by the time of his death.