She lived in Australia until 1859, when she returned to Ireland, spending her final years in the Sisters of Charity Mother House in Dublin.
When De Lacy joined the order, she expressed her interest in traveling to Australia, and participating in the establishment of the new congregation.
Three other Sisters volunteered: Mother John Cahill, who became the superior of the congregation; F. De Salca O'Brien, Lawrence Cator.
[12][3] The sisters lived in austerity; they were dependent on dispensations of money from Bishop Polding who controlled the funds sent from Ireland to support the convent.
De Lacy was one of the Sisters involved in establishing the first orphanage run by the order, the Catholic Orphan School, located in Waverly, New South Wales.
She took notes based on her visitations with the convicts; these original records have been preserved, and offer a valuable window into the events and conditions of the time.
[1] The hospital was designed to serve the poor, and accepted patients of all religious backgrounds, which was in keeping with the approach taken by Mary Aikenhead in Dublin.
[1] In 1859, a conflict emerged that led to De Lacy's removal from her post at St. Vincent's Hospital, and her subsequent return to Ireland.
[16] The superior of the Sisters of Charity subsequently removed De Lacy from her role as the hospital rectress, or administrator.
It was suggested by some that there were other factors at play, and that ongoing tension between De Lacy and Archbishop Polding contributed to her removal.
[1] A Heritage Center honoring the work of the Sisters of Charity in Australia has been established in Potts Point, Sydney, New South Wales.