She was the second eldest child of ten surviving children of John Stanislaus Joyce and Mary (née Murray).
Joyce's difficulties in raising the younger children with her father was the basis of the "Eveline" story in Dubliners.
[1][2] Joyce entered the Convent of Mercy Missionary College, Callan, County Kilkenny on 20 August 1909.
James was in Dublin at the time of her departure, and saw Joyce off from North Wall to England where she would sail to New Zealand.
[2][3] On 30 December 1909 she entered the Convent of Mercy, Greymouth, New Zealand, receiving the habit on 13 July 1910.
[4] She had never read any of her brother's works,[2][3] possibly until 1962, when Fr Godfrey Ainsworth gave her a copy of A portrait of the artist as a young man.