Sweeney, Joseph Aloysius (1897–1980), republican and army officer, was born 13 June 1897 in Burtonport, Co. Donegal, son of John Sweeney, general merchant, and Margaret Sweeney (née O'Donnell). His father remarried after his mother's death, and along with a sister he had one step-brother and two step-sisters. He was educated at Burtonport national school, at St Eunan's, Letterkenny, and at St Enda's, Rathfarnham, Dublin. The decision to send him to St Enda's was consistent with his family's strong nationalist views; his father had been jailed during the land war, was president of the local branch of the AOH, and a founder the Irish Volunteers in Donegal. At St Enda's Joseph was greatly influenced by the school's founder, Patrick Pearse (qv), who stirred him to even more radical nationalism than did his father. On his return to Donegal for the summer holidays in 1914 he joined the local Irish Volunteers. The following September he transferred to E Coy, 4th Bn, Dublin Bde, who styled themselves ‘Pearse's own’. He was in his first year of an engineering degree at UCD, but his studies were largely neglected in favour of his activities on behalf of the Volunteers. Still in residence at St Enda's, he acted as courier for Pearse, primed cartridges, and purchased chemicals with which he then helped to make explosives. He joined the IRB at the end of 1915, being sworn in by Pearse.
On Holy Thursday 1916 he was given mobilisation orders to deliver for the following Sunday. He fought in the GPO during the rising, and after the rebels had surrendered he was one of the stretcher-bearers for the wounded James Connolly (qv). He was imprisoned in Stafford jail and later at Frongoch camp, where his commitment to radical nationalism was confirmed and he met many activists, including Michael Collins (qv). In October he resumed his studies at UCD and rejoined E Company. During the summers he worked on the reorganisation of the Volunteers in Donegal and was made commandant of the west Donegal battalion. Following a serious bout of influenza (1918), he gave up his studies and moved home, taking up the post of office accountant in his father's firm. In that year he was appointed commandant of the No.1 Brigade and was elected Sinn Féin MP for Donegal West at the general election. When the first dáil met in January 1919, Sweeney was its youngest member. In March 1920 he was arrested and jailed, briefly in Belfast before being transferred to Wormwood Scrubs, London. He participated in the mass hunger strike of April 1920 and was released. In May 1921 he was appointed officer in command of 1st Northern Division.
After the truce, his admiration for Collins and discussions among his colleagues in Donegal swayed him to support the Anglo–Irish treaty. In the lead-up to the civil war he was involved in smuggling arms across the border to northern nationalists, and became involved in clashes with British troops along the border; seven of his men were killed at Pettigo as a consequence of such a clash. During the civil war he was general in charge of the national army in the north-west; during his period of command four republican prisoners were executed without trial in Drumboe, Co. Donegal. He was also responsible for the execution of his friend, Charlie Daly, which affected him badly. He later commented on the civil war that ‘I've tried to wipe it out of my mind as much as possible’ (Griffith & O'Grady, 306).
He chose not to run in the 1923 general election; remaining in the army, he became GOC Donegal Command (January 1923–March 1924), and was acting chief-of-staff for ten days during the army mutiny of 1924. Between then and October 1927 he had two spells as GOC Curragh Command, interrupted by a period as GOC Western Command. Appointed adjutant-general in October 1928, he became quartermaster-general in February 1929 and chief of staff in June 1929. His term as chief of staff coincided with the political rise of Fianna Fáil, and later he was anxious to insist that the will of the people would have been protected under his command. He served as general officer in the Curragh, Kilkenny, Athlone, Sligo, and Galway districts from 1931 to 1938. After a brief spell as GOC Western Command, based at Athlone, he retired from the army in December 1940.
On leaving the army he settled down in 26 Orchardstown Park, Templeogue, Dublin, working as an insurance inspector for the Canada Life Assurance Company for ten years, before being appointed area officer of the Irish Red Cross Society in 1950. He became general secretary of the society in 1956 and held this position until his retirement in 1962. During his term as general secretary he was involved in transporting Hungarian refugees to Ireland. A devout catholic, he was a member of the third order of St Francis. A member of the Michael Collins Memorial Committee, he also acted as president of the 1916–21 Club. He had two sons and a daughter. He died 25 November 1980 at St Vincent's private nursing home, Dublin, and was buried with full military ceremony in his native parish.