The Sisters of Mercy were founded in Ireland in 1831 by Catherine McAuley, an extraordinary woman with a deep trust and faith in God. Her leadership and inspiration is internationally recognised and honoured. The first Sisters of Mercy arrived in Auckland in 1850 and immediately began their teaching mission, establishing St Mary’s College based on Mercy values.

Today the College is owned by the Sisters of Mercy who have established a Board of Directors which works in conjunction with the Board of Trustees to ensure that the Catholic Character and Mercy charism of the school is not only maintained but enhanced and promoted.

St Mary’s College is the oldest existing secondary school for girls in Auckland and one of the oldest existing schools in New Zealand. It was established by a group of pioneering Sisters of Mercy who arrived from Ireland on 9 April 1850. The following day they began their work of teaching in a building on the site of the present St Patrick’s Cathedral in Wyndham Street, Auckland.  (The works of the Sisters include education, care of the sick, visitation and pastoral care of prisoners). The Sisters continued to teach there while the St Mary’s Ponsonby property was developed: a name which became attached to the school. In the college the classrooms, including a stage, were divided by folding doors, which could be opened to form a roomy hall used for concerts and prizegivings, These occasions were often graced by the presence of the Governor of the Auckland Province and his Lady.