[4] He served in the Governor General's Foot Guards,[5] before signing attestation papers for service overseas on 1 February 1915, and was assigned to the 38th Battalion, Canadian Expeditionary Force,[6] with the rank of lieutenant.
On 2 January 1917 Bell was seconded to the Royal Flying Corps as an observer on probation, also being attached to the Eastern Ontario Regiment.
[8] Flying in a F.E.2b two-seater Bell gained his first aerial victory on 8 April, with Lieutenant L. W. Beale as pilot, sharing with five other aircraft of his flight in the destruction of an Albatros D.II over Regny.
[3] On 3 May, with Second Lieutenant E. A. H. Ward as his pilot, he destroyed an Albatros D.III,[3] and on 15 May his period of probation came to an end and he was appointed a flying officer (observer) with seniority from 9 January.
His citation read: On 29 February 1919 Bell appeared before a Medical Board, having contracted malaria in Salonika in September 1918; he suffered from intermittent fevers, weakness, and insomnia, and was assessed as being unfit for further service.
[4] On 10 October 1919, he received unrestricted permission to wear the insignia of a Chevalier of the Legion of Honour, conferred on him by France.