Christian Fleck was 38 years old when he enlisted. He had been born in Peckham, London, to Christian Fleck and his wife Emily, nee Reed. He grew up in London and in September 1905, married Emily Prudence Bean at St. Georges, Hanover Square. Their daughter, Phyliis Wilhelmina Fleck was born in 1906. The family arrived in Melbourne as unassisted immigrants, arriving on board the Makarini on 20 July, 1912.

Christian was by occupation, a labourer, living in 1917 at 1127 Punt Rd., East Melbourne with Emily amd Phyllis, when he enlisted on 19 February, 1917, and was attached to the 19th Reinforcements to the 21st Battalion. The Reinforcements embarked for England on 11 May, on board HMAT Ascanius A11, disembarking at Devonport on 7 July, 1917.

From Devonport, they marched out to Rollestone, joing the 6th Training Battalion for nine days further training. Christian Fleck, however, went AWL from 23rd to the 27th July, and was duly charged and punished. He was then transferred from the 21st Battalion to the Machine Gun Details at Grantham for training and was taken on strength on 31 October, 1917, with the 4th Machine Gun Battalion. This unit had been formed in France on 2 March, 1918, along with the 12th, 13th and 24th Machine Gun Compannies.

Christian Fleck remained in England for another four months before proceeding from Folkestone overseas to France on 28 February, 1918. He had again gone AWL from 5 - 6 February, earning ten days' detention . On 6 March, 1918, he was taken on strength with the 12th Machine Gun Company, and took part in the action to halt the German Spring Offensive on the Somme. On 8 August, he was wounded in action, receiving a gunshot wound to the right leg. At this time, the 4th Machine Gun Battalion were around Harbonnieres/Bayonville, close to Villers-Bretonneux.

Fleck was sent back to England and admitted to the 1st Southern General Hospital at Stourbridge on 12 August. The injury was sufficiently bad that he was invalided out of the army, marching out to Sutton Veney on 3 March, 1919, then leaving on board the HS Fort Denison on 25 March, disembarking in Melbourne on 10 May. In 1919, Christian and Emily Fleck were living  at 82 Melville Street, Hawthorn, but by 1931 they had moved, with Phyllis, to 123 Pachingham Street, Kew. Christian was working as a labourer, while Phyllis was a factory hand, and emily kept house. By 1936, they were still in Kew, but Christian was now a psotal employee. They stayed in Kew until the late 1940s, though Phyllis had moved by 1943. Christian Fleck died in Fitzroy in 1958, aged 77. Emily died in 1968, where she had been living at 6 May St., Doncaster.