James Donnan enlisted on 15 July, 1915. It is a significant date, because it follows on from the assault on the Gallipoli Peninsula. James Donnan would have read the news and seen the casualty lists and therefore had full knowledge of his possible fate. Moreover, he was 44 years old and had already served in an earlier war, having served in the 4th Battalion for one year during the South African conflict. He was a single man and described himself in his enlistment and embarkation papers as both a labourer and a general hand. He gave as his next of kin, his stepfather, F.A. Bolton, living in Nelson St., Williamstown. 

He joined the 29th Battalion, raised after a recruiting campaign. It was formed at Broadmeadows Camp in Victoria on 10 August 1915, as part of the 8th Brigade, with the recruits mainly coming from the Melbourne suburbs. After training at Broadmeadows, they embarked for Egypt on board HMAT Ascanius A11 on 10 November, disembarking at Port Suez on 7 December, 1915. In Egypt, 8th Brigade joined the 5th Division and were initially used to defend the Suez Canal against the Ottoman forces, but also undertaking  further training before proceeding to France on 14 June on board HMT Tunisian. They disembarked at Marseilles on 23 June, 1916, were transported by rail to Hazebrouk, and then had a diffilcult 29 Mile (47k) march on cobbled roads, carrying packs weighing up to 75 pounds (34k) before arriving at the front on 10/11 July.

Here they relieved the 13th Battalion and, on 19 July, saw their first major action attacking German forces at Delange Farm, part of the battle of Fromelles, which was itslef part of the Somme capaign. it was to be remembered as 'the worst 24 hours in Australian History', with official war historian C.E.W. Bean concluding that 'the value of the result, if any, was tragically disproportionate to the cost of the attack'.

While the Australian divisions initially captured 1,000 yards of enemy trenches, the overnight counter attack by the Bavarian troops led to a bloodbath. In a few hours and a single night, there were 5,333 casualties, and 400 men captured. Two battalions, the 60th and the 3rd, lost 90% of the fighting strength. The 29th Battalion held the line for eleven days before being relieved. Like the other battalions on the front line, they suffered many casualties: 52 men killed in action, 164 wounded. The Fifth Division was so badly depleted that they were withdrawn from the front and spent then next few months behind the lines, building up again.

James Donnan had been one of the lucky ones, escaping uninjured. However, in October, the 29th was once more in battle and, on 31 October, he was killed in action at Caterpillar Ridge, part of the battle for Amiens. He was buried at Caterpillar Valley Cemetery, Longueval, France, in Plot 13, Row A, Grave 31. He is also listed in the AWM145 Roll of Honour Cards and listed in Panel 115 of the Commemorative Area at the Australian War Memorial.

After his death, a dispute emerged amongst his family as to who should be given his medals and the memorial plaque and scroll. He had named his stepfather as next of kin, but a brother, John Donnan, a newspagent and stationer at Mirboo North, Victoria wrote to the army authorities in 1920, saying 'I do not wish the War Medals to go to my stepfather, F.A. Bolton and beg to request that you will not permit same to go to him and to protect my interest in the matter.'(17/1/1920) Mr. Bolton, however, replied ' ... if it were possible to ask, he (James) would prefer me to have the medals. I may add that we were always the best of friends'.(16/12/1920) As the named next of kin, the medals were sent to Mr. Bolton.