In 1864 he laid claim to the property now called Dalgonally in North-West Queensland, and found evidence of Ludwig Leichhardt's final expedition.
At the time he was superintendent of Glengower, a property near Castlemaine owned by Donald Campbell, a brother of his Aunt Elizabeth.
McIntyre's party left Glengower and made for Mount Murchison (near modern day Wilcannia) on the Darling River, and then for Cooper Creek.
The party consisted of Duncan McIntyre (leader), William Frederic Barnett (second in command), Albert, Charlie and Billy (aboriginals), and 25 horses and one kangaroo dog.
With McIntyre somewhere in Queensland – and still oblivious of his new role as leader – the Leichhardt search party left Glengower on Monday, 3 July 1865, at midday.
In a letter to Donald Campbell dated 24 August 1865, McIntyre describes his movements:[5] I have been up in Queensland and bought a lot of cattle from a station near the Barcoo River.
The party split in two: McIntyre and one other man moving ahead on camels and planning to return with water; the second group, led by Dr James Murray, coming along behind with the horses and stores.
When the two groups met again, the expedition in its original composition was at an end: 66 horses dead in the desert, and stores and equipment scattered.
Donald McIntyre, Barnett, McCalman, Dr Murray, a Black Boy and I travelled until our horses gave out.
When the cool of the night came on we got a little stronger and we crawled along the tracks until we met Belooch with a little water which gave us great ease.
On 9 February the expedition left Cooper Creek with 12 camels, 5 horses, nearly two tons of stores and six men: Duncan McIntyre, John McCalman, William Barnett, Belooch, Welbo and Myola (three aborigines).
[7] To make good the loss of equipment that occurred at Cooper Creek, McIntyre went to Burketown towards the end of April 1866.
Dalgonally Station (then occupied by Duncan's brother, Donald McIntyre) became the base for the expedition and several rivers were investigated in the search for Leichhardt.
Ulick Browne Snr remembered the occasion:[8] I am pleased to have witnessed in 1918 the arrival at Julia Creek of the monument now erected at the Grave Hole, put there by the family, the proceedings directed by Mrs Annie McKay.
Bill Horton, teamster, carted the monument on his tabletop waggon with a 19-horse team (no lorries then); and Bill Norton, butcher and handyman of Julia Creek, erected it.The inscription reads: In memory of Duncan MacIntyre [sic][9] who, while leading an expedition in search of Leichhardt organised by the Ladies of Melbourne, died here on 4th June 1866 aged 34 years.
He was a man of promise, of courage and integrity, and whilst beset with difficulties, pushed on faithfully until struck down by fever and death, being attended at the last by his brother, Donald MacIntyre of Dalgonally, to whom also this stone stands in memory.
He left a wife and family by whom this stone is erected in loving memory.Gus am bris an la agus an teich na sgailean.