Byrne, Sir Joseph Aloysius (1874–1942), soldier and administrator, was born 2 October 1874 in Co. Londonderry, son of Dr Joseph Byrne, DL, a catholic physician of Londonderry, and Emily Byrne (née Egan). He was educated at St George's College, Weybridge, Surrey, England, and Maison de Melle in Belgium. In 1893 he joined the Royal Inniskilling Fusiliers and in 1899 fought in the South African war, where he was wounded in the siege of Ladysmith. After the war he remained in South Africa and in 1903 was employed with the Central Judicial (Claims) Commission in Pretoria. Returning to England, he served as assistant adjutant-general at the war office and was granted the rank of brevet lieutenant-colonel on 1 April 1915. In Dublin, during and after the 1916 rising, he held the rank of brigadier-general in the Irish command while acting as deputy adjutant-general.
He was appointed inspector-general of the RIC in 1916 and initiated a policy of compulsory retirement of men considered unfit for service. It was a mixed success, with the benefits of streamlining contrasting sharply with the subsequent damage to morale. As violence intensified, Byrne came into conflict with political and military policies – particularly plans to recruit police outside Ireland and form special forces – and on returning from a month's leave (January 1920), he was suspended on full pay, along with a number of other senior catholic policemen. His removal drew strong public and press criticism.
He was called to the bar at Lincoln's Inn (1921) and in June 1922 was appointed British governor in the Seychelles, a position he retained until 1927. While there he helped provide a modern hospital on the principal island of the group. He was promoted to governor of Sierra Leone (1927) and helped to develop that country's mining and agricultural industries before the end of his term in 1931. In that same year he was appointed governor and commander-in-chief in Kenya, and despite suffering several bouts of ill-health remained in office until his retirement (1936). Viewed as a governor who combined firmness with humanity, he was involved in several conflicts with European settlers in Kenya. The most notable of these was his eventually successful attempt to impose income-tax payments on the settlers, in the belief that the burden of the colony's finances was unfairly carried by the native population.
Byrne's honours included CB (1917), KBE (1918), KCMG (1928), and GCMG (1934). A keen hunter, fisherman, and golfer, he died at Weybridge, England, 13 November 1942. He married (1908) Marjorie Joseph of Cairo, Egypt; they had one daughter.