 She entered St Leo's Convent, in Carlow in 1838, becoming a Sister of Mercy, and taking on the religious name of Mary Cecilia Maher.In 1849 Bishop Pompallier visited seeking nuns to emigrate; eight left from St Leo's, led by Maher.They travelled to New Zealand, learning Māori along the way, establishing the Sisters of Mercy in Auckland as the first female religious community in New Zealand in 1850.