Catherine McAuley was born at Stormanstown House near Dublin on 29 September 1778 to James and Elinor McAuley. Both parents died before Catherine, and her younger sister and brother, Mary and James reached adulthood, and, while living with relatives, the three of them experienced wealth, bankruptcy and poverty as well as a strongly anti-Catholic atmosphere. When Catherine was twenty-five, a retired Quaker couple, William and Catherine Callaghan, invited her to live with them at Coolock, an estate not too distant from the centre of Dublin. Catherine proved to be a loving companion until their deaths, and when Mr. Callaghan died in 1822, he bequeathed his entire fortune to her.
It was this inheritance which made it possible for Catherine to build the House of Mercy which still stands on the corner of Lower Baggot and Herbert Streets in Dublin - the founding House of the Sisters of Mercy. On 24 September 1827, Anna Maria Doyle, an acquaintance, and Catherine’s relative, Catherine Bryn, moved into this residence which was both a school for children and a shelter for girls in need. Catherine came daily to help, while continuing to care for her late sister’s children. In September 1830, with Anna Maria (Doyle) and Elizabeth Harley, Catherine began the formal training necessary to establish a new Order of women religious.
The Order of the Sisters of Mercy was born when the three Sisters made their Profession of Vows on 12 December 1831. Pope Gregory XVI formally approved the Mercy Rule and Constitutions on 6 June 1841. In September 1841, Catherine’s right lung was diagnosed as "diseased" and by the end of October she was quite ill and was anointed on November 8. As she lay dying on November 11, she made one last request and asked a sister to tell the community to "get a good cup of tea-I think the community room would be a good place-when I am gone and to comfort one another-but God will comfort them." She died on the evening on 11 November 1841 and was buried in the cemetery at Baggot Street., Dublin, Ireland.