Arnold was the son of Harry Greenwood, of Lower Giles Hill Farm, Shelf, Halifax.
On the 1901 census the family were living at 7 Chapel Street, Arnold, aged 2, had an older brother and sister as well as a younger sister. 1911 saw the family living at Ing Head Cottages Queensbury. The family had a fifth child, a boy. Arnold, aged 12, was in occupation as a doffer.
Enlisting in Halifax, Arnold served in 2nd/8th Battalion. West Yorkshire Regiment (Prince of Wales’s Own). The Battalion were known as the Leeds Rifles.
In February 1918 the 2nd/8th were absorbed by 1st/8th Battalion, who in turn transferred from the 146th Brigade, 49th (West Riding) Division to the 185th Brigade, 62nd (2nd West Riding) Division, and were renamed the 8th Battalion.
Arnold was killed in action on 27th September 1918. His battalion had moved forward at 08:15hrs to push through the enemy lines and capture the village of Marcoing. The battalion war diary gives a detailed account of the action which was a success. As well as many prisoners, they captured 15 field guns and 9 machine guns.
The battalion casualties, killed/wounded/missing, were 11 officers and 341 other ranks. Arnold Greenwood is buried at LOWRIE CEMETERY, HAVRINCOURT (G. 6).