Reginald qualified as a civil surgeon in 1902. He gained a commission in the Medical Services on the 1st March 1906, and was serving under the rank of Major when war broke out. He entered the war in France on the 19th August 1914, with No 1 Casualty Clearing Station and served with them until 1915, when he was invalided home. On 28th August 1915, he joined the 63rd (2/2nd West Lancs) Field Ambulance at Beachy Head, and returned with them to France as their Commanding Officer. He left the unit on 17th March 1916 [the unit history advising he had been appointed as D.A.D.M.S. to another Division]. He transferred to No 18 Casualty Clearing Station, serving with them until 1919. From the 3rd October 1915 - 15th March 1916 and from the 9th September 1916- 14th March 1919, he served under the rank of temporary Lieutenant Colonel. Reginald then went to Malta. He gained full promotion to Lieutenant Colonel in 1924.