Edwin Campbell Johnson was the second son of Alexander Campbell Cusac Johnson and his wife, Ella May, nee Young. He was born on 13 May, 1892 in Adelaide and baptised at St. Mary Magdalene's, Adelaide. At the time he enlisted, on 1 May, 1916, he was 24 years and 4 months old, working as a clerk. He had also left Adelaide for Melbourne, where he married Elsie May Johnson, nee Stubbs, a widow, on 5 June, 1915 at St. James Old Cathedral, West Melbourne. At the time he enlisted, she was living at 68 Clarendon St., East Melbourne, the only connection they had with East Melbourne.

Edwin Johnson had some previous experience in the military prior to enlisting for service abroad. He had already spent a year, with the AIF, his Attestation paper signed on 30 August 1915, serving as Sergeant-Major to the 16/10th Infantry, then as paymaster and clerk. Following training at Duntroon 1916, he was recorded as having 'conduct and work excellent'. He was given a Commission to be Lieutenant on 10 June, 1916, and left for abroad from Adelaide on 21 September that year on board HMAT A73 Commonwealth. He disembarked at Plymouth on 14 November and on 27th of that month was 'On Command' at Tidworth. On 21 January, 1917, he was sent to France and taken on strength with the 32nd Battalion, on 27th January.

The 32th Battalion, was raised in 1915, made up of volunteers from South Australia and Western Australia. A and B Companies were from South Australia, C and D, from Western Australia, so it is  probable that Edwin Johnson's initial officer training with the 32nd Battalion was in South Australia  in 1915,with the newly formed 32nd Battalion. The 32nd left for Egypt in November 1915 on board the transport ship HMAT Geelong, arriving after the Gallipoli campaign had ended. They were re-organised and became part of the 8th Brigade, attached to the 5th Division, then left to join the war at the Western Front. The 32nd Battalion took part in the fighting at Fromelles in July, 1916, suffering 718 casualties, roughly 90% of its fighting strength, As a result, they were used in a support role for the rest of 1916, losing more soldiers due to trench warfare. Winter 1916-1917, when Edwin Johnson joined the 32nd, they were on defensive duties at the Somme and took part in the pushback of German forces to the Hindenburg Line. In May, 1917, they fought in the 2nd Battle of Bullecourt. 

On 26 September, the 32nd Battalion was heavily committed to fighting at Polygon Wood, near Ypres, during the battle of Passchendaele. It was here that Edwin Johnson died, struck down by a direct shell hit to the trench in which he was sheltering. 

The Red Cross files tell his story:

Lieutenant Johnson was wounded by a shell on 30th Sept. about 10 o'clock at Polygon Wood and died at 2nd Dressing Station. I can't say as to burial, but sure to have been buried as they were burying all those who died there about the station. I came away the next day. Witness A E King 3828 32nd Battalion

On 30th September we were holding trenches at Polygon Wood. A shell came right into Lt. Johnson's dugout, killing him outright. His batman was with him. He lost his legs. Private L.R.Chase 32nd Battalion AIF

Lt. Johnson was in B Coy. XV pit and  he was my officer. It was whilst we were holding Polygon Wood on 30th September that Mr Johnson was dangerously wounded in the side and also in the head. I helped to put him on a stretcher and he said to us 'Goodbye, lads' and he was then taken to D/S. I heard afterwards that he had D/W. I do not know where he was buried, but I have seen the cross which was made for his grave and also the wreath that was sent. Pte. W.G.Kerr, 6535, 32.D.XV, No. 13 Gen. Hop. Boulogne, 8/12/17

Edwin Johnson's brother, James Alexander Campbell Johnson, had also enlisted, but in Britain, in August 1914, joining the King's Liverpool Regiment in the BEF. He was also killed in action, on 21 August, 1918. Edwin Johnson was buried at the Birr Cross Military Cemetery, Flanders, Belgium.