Harry enlisted on 26th October 1915. He was 19 years old, and was living in Havelock House, Spencer Street, Burton Latimer, Northamptonshire at the time. He embarked at Southampton on 1st March 1916, then disembarking the next day at Rouen, entered the war in France on 2nd February 1916. He was posted to serve with the 141st Field Ambulance, joining them in the field on the 4th March 1916. On 12th January 1919 he proceeded to England for demobilization, arriving on the 20th January. He was transferred to Class Z Reserve on 16th February 1919.