Barry, Mother Mary Gonzaga (1834–1915), pioneer Loreto sister in Australia, was born Mary on 24 July 1834 in Wexford town, the eldest of seven children of John Barry, bank manager, and Elizabeth Barry (née Cowan). Mamie, as she was known, lived with her maternal grandmother and aunts in Liverpool for two years from the age of five. Upon her return to Enniscorthy, Co. Wexford, she was educated at home by her maternal aunt, Kate Cowan, and also attended a local school run by the Misses Murdoch. The family later moved to a newly built bank in nearby Castle Hill. Barry attended boarding school at the Loreto Convent, Gorey, Co. Wexford (1848–51), and the Loreto Abbey, Rathfarnham, Co. Dublin (1851–3). She entered the Loreto order at the Gorey convent on 24 August 1853, and upon profession took the religious name, Mary Gonzaga. She served as mistress of novices and as superior of the Gorey convent (1867–72) and of the Enniscorthy convent (1872–5). When in 1875 James Moore, the first catholic bishop of Ballarat, asked the Loreto sisters to open a convent in his newly created diocese, Barry and six other sisters were sent to pioneer the teaching order in Australia. For the first 12 years (1875–87) Barry concentrated her efforts in the Ballarat diocese and focused on female education, establishing a catholic training college for teachers at Dawson Street, Ballarat (1884). In 1896 she invited Barbara Bell, a graduate of the Secondary Teachers’ Training College, Cambridge, England, to teach at the college. Loreto sisters supervised teaching in other Ballarat parochial schools and Barry also established confraternities for adult catholics. From 1887 the order began to expand throughout Australia, founding ten convents by 1905.
On 1 May 1906 the order opened the Central Catholic Training College in Albert Park, Melbourne, in response to a request by the catholic bishops of Victoria in the wake of a 1905 government regulation which required the registration of all teachers. It was unique in Victoria in providing for both lay and religious women who wished to study teaching or pursue a university education. Barry was also a pioneer in kindergarten education which she had observed in Europe and introduced innovative educational methods at Mary's Mount Abbey in Ballarat before 1900. In 1912 she established a free kindergarten in south Melbourne, aided by volunteers from the Loreto Past Pupils' Association which she had founded in 1898.
She returned to Ireland four times during her time in Australia: in 1887, 1894, 1907, and 1913. Under Barry's leadership, the Loreto order was recognised for its significant contribution to catholic education in Australia. She became ill in 1914, died six months later on 5 March 1915, and was buried in the convent grounds at Mary's Mount, Ballarat.