In March 1917, MacGreevy enlisted in the Royal Field
of the British Army. His training lasted for nearly
In November of that year he received a commission
as Second Lieutenant in the RFA
and one month later, having finished home service,
was posted to the Western Front,
landing in Le Harve on 20 December 1917.
January 1918 MacGreevy was serving with the 148th
Brigade in Flanders. He was twice
first on 25 April 1918,
and more seriously at Messines
on 2 October where he received a shoulder wound.
On 8 October he was sent to an officers' hospital
in Manchester to recover, and in December
was moved to a convalescence home near Scarborough.
He spent Christmas 1918 in Tarbert,
and on 22 January 1919 was demobilised.