Henry was educated in the medical school of the Royal College of Surgeons in Ireland, and took the diplomas of L.R.C.P. and S.I. in 1892. After serving as medical officer in Basutoland, and as a civil surgeon in the South African Field Force in 1900-1902, he went into practice in Dublin, where he was demonstrator of anatomy to the Royal College of Surgeons in Ireland, as surgeon to the Royal City of Dublin Hospital, and as surgeon to the Westmorland Lock Hospital. He had also been surgeon to Mercer’s Hospital, Dublin. He took a temporary commission as lieutenant in the R.A.M.C. on 11th August 1914. He entered the war in France on 20th August 1914 with No 1 General Hospital, and served with them until 20th October 1914, when he left for duty with No 4 Motor Ambulance Convoy, being struck off the strength of the hospital. On 9th March 1915 he joined the 16th Field Ambulance. On 8th June 1915 he was one of the officers of “B” Section to open an Advanced Dressing Station in a large residential house in Vlamertinghe. He gained promotion to the rank of temporary Captain on completion of a year’s service, on 11th August 1915. On 6th October 1915 he proceeded to Boulogne for temporary duty under the orders of D.D.M.S. 6th Corps. - returning on the 12th. From 26th January to 24th February 1916 he had a few temporary postings to serve at the prison, Ypres, then on 1st April 1916 held a lecture to young officers on water cart duties, water testing & duties of Regimental M.O. On 19th April he was serving in the Advanced Dressing Station. [A.D.S.] On 1st June 1916 he took over an Advanced Aid Post at the Canal Bank, Poperinghe. along with a Sjt and 5 privates. where it was later noted that he had improved accommodation there for patients. On 16th July 1916 he gave lectured on first aid and the treatment of wounds. On 15th August 1916 he, along with about 30 O.R.s, left Acheux to compete establishment of A.D.S. at Mailly-Maillet, an aid post at Auchonvillers, and the trenches. The unit was at Maltz Horn Farm on 18th September 1916, and owing to wet weather the horse ambulances had great difficulty in traveling and transporting casualties back down the line. After requesting permission he established himself, with a few nursing orderlies, at the crater, where, it was reported, he did most excellent professional work. He was posted for temporary duty with No 33 Casualty Clearing Station, rejoining his unit on 13th December 1916. 4 days later, on the 17th, he took charge of Harley Street, A.D.S. The station was handed over to the 18th Field Ambulance on 28th December, when he and his personnel returned to H.Q. On 18th April 1917 he went for temporary duty with the 18th Field Ambulance, and on the 23rd reported to the Officer Commanding the 18th Field Ambulance for duty at the A.D.S. Philosophe. On 24th August 1917 he, along with 20 O/Rs marched at 1.30pm as an advance party of 16th Field Ambulance to Maroc. The following day he received orders to proceed with his party, increased by 4 additional stretcher-bearers,, to take on the A.D.S. at St Patrick’s, Loos, along with Solent Post, Australian Tunnel, and conjoint R.A.M.C. posts & a R.A.P. at Hill 70. On 5th September 1917, he and all the A.D.S. staff were gassed and had to be relieved. They were all admitted to hospital. He rejoined for duty on 24th. On 19th November 1917 he, along with “C” Subdivision, proceeded to set up a Walking Wounded Corps Post at Queen’s Cross. On 25th November he took over from Capt Scott M.C. as Medical Officer of 11th Leistershire Regiment. On 3rd December 1917 he and 2 nursing orderlies went up to the A.D.S., Marcoing to supplement the personnel of the 17th Field Ambulance there. He returned to H.Q. on the 6th December. 2 days later, on 8th December, he set up a dressing station in a dugout, with accommodation for 12 stretcher cases. On 4th January 1918 he was appointed the rank of acting Major. The field ambulance moved to Courcelles on 15th January 1918, where he set up a tent subdivision. On the 28th he was posted to serve at the A.D.S. From 16th February to 3rd March 1918 he took up temporary command of the unit. He re-assumed command of the unit on 15th March 1918, and was appointed the rank of acting Lieutenant-Colonel whilst in command of a medical unit. The unit war diary records him being awarded the Distinguished Conduct Medal on 14th May 1918. It was awarded “For conspicuous gallantry and devotion to duty. He went through heavy machine-gun and rifle fire to a dressing station which was being evacuated, and cleared a large number of wounded. He also took cars to battery positions which were being shelled, and removed the wounded to safety. At the dressing stations during enemy bombardment he remained to the last, and saved many lives by his courage and devotion to duty.” He was severely wounded on 22nd May 1918 and evacuated to a CCS.