Henry enlisted into the Medical Staff Corps on 19th November 1894. He was a Cook by trade at the time. He first saw active service in South Africa from 1899 to 1902, gaining the Queen's and King's South African Medals. On 21st January 1904 he was appointed the rank of Lance Corporal, then gained promotion to the rank of Corporal on the following 1st April. He entered the war in France on 15th August 1914, as part of the Regimental Medical Officer's team for the 9th Lancers. On 12th October 1914 he was appointed at the rank Lance Serjeant, then gained promotion to the rank of Serjeant on 6th February 1915. He was discharged from the R.A.M.C. on 2nd February 1917. Also served with the Ox and Bucks Light Infantry.