McElroy was born at
Donnybrook, County Dublin, Ireland, to Samuel and Ellen McElroy. He enlisted promptly at the start of World War I in August 1914, and was shipped out to
France two months later. While serving in the
Royal Irish Regiment On 1 June 1916, McElroy relinquished his commission in the Royal Irish Regiment when awarded a cadetship at the
Royal Military Academy, Woolwich, from which he graduated on 28 February 1917, and was commissioned as a second lieutenant in the
Royal Garrison Artillery.
Aerial service McElroy was promptly seconded to the Royal Flying Corps, being trained as a pilot at the
Central Flying School at
Upavon, and appointed a
flying officer on 28 June. On 27 July his commission was backdated to 9 February 1916, and he was promoted to lieutenant on 9 August. On 15 August he joined
No. 40 Squadron RFC, where he benefited from mentoring by
Edward Mannock. He originally flew a
Nieuport 17, but with no success in battle. By the year's end McElroy was flying
S.E.5s and transferred to
No. 24 Squadron RFC. He continued to steadily accrue victories by ones and twos. By 26 March, when he was awarded the
Military Cross, he was up to 18 "kills". On 1 April, the Army's Royal Flying Corps (RFC) and the
Royal Naval Air Service (RNAS) were merged to form the Royal Air Force, and his squadron became
No. 24 Squadron RAF. McElroy was injured in an accident on 7 April; he brushed a treetop while landing. By then he had run his score to 27. While he was sidelined with his injury, on 22 April, he was awarded a bar to his Military Cross. Following his
convalescence, McElroy returned to No. 40 Squadron in June, scoring three times, on the 26th, 28th, and 30th. The latter two triumphs were observation balloons. That ran his tally to 30. On 26 July, his mentor and friend,
Edward "Mick" Mannock, was killed by ground fire. Ironically, on that same day, "McIrish" McElroy received the second Bar to his Military Cross. He was one of only ten airmen to receive the second Bar.
Death in action McElroy's continued apparent disregard for his own safety when flying and fighting could have only one end. On 31 July 1918, he reported destroying a
Hannover C for his 47th victory. He then set out again. He failed to return from this flight and was posted missing. Later it was learned that McElroy had been killed by
ground fire. He was 25 years old. McElroy would receive the
Distinguished Flying Cross posthumously on 3 August, citing his shooting down 35 aeroplanes and three observation balloons. The Bar would arrive later, on 21 September, and would laud his low-level attacks. In summary, he shot down four enemy aircraft in flames and destroyed 23 others, one of which he shared destroyed with other pilots. He drove down 16 enemy aircraft "out of control" and out of the fight; in one of those cases, it was a shared success. He also destroyed three balloons. McElroy is interred in Plot I.C.1 at the
Laventie Military Cemetery in
La Gorgue, northern France. ==Awards and citations==