Alexander enlisted on 6th August 1914. He was 24 years old and a Clerk by trade. He entered the war in France on 7th October 1914, as part of the team for the Assistant Director of Medical Services, 7th Division. On 31st August 1916 he was wounded from a shell explosion in Delville Wood and evacuated back to the UK. On 23rd April 1917 he was transferred to Class "P" Army Reserve.