Born July 1, 1831 in Kingston, Ontario, Sister Teresa (Margaret) Brennan was the first Canadian-born member of the Sisters of St. Joseph of Toronto and also their first Canadian-born superior general.
In 1852 she entered the Sisters of St. Joseph in Toronto and received the habit and her religious name of Sister Teresa on October 15th. This small community of nine members, including the four who had arrived the previous year from Philadelphia, served the orphans, homeless and sick of the city. After teaching at St. Paul’s school for three years, Sister Teresa was appointed superior of the orphanage and then in 1858 was named superior general by the Toronto Bishop de Charbonnel.
While concerned daily with the management of the new House of Providence (1857), Mother Teresa established a new convent and school in Oshawa in 1858 and oversaw the tremendous growth of the congregation in Toronto. In response to this growth, a new motherhouse was built during her second term on land donated by the Hon. John Elmsley from his Clover Hill Estate. It included a novitiate and boarding school.
Mother Teresa resigned as superior general in 1863 and continued to serve her community as mistress of novices and then in later years as the local superior for communities in St. Catharines, London and Barrie, Ontario. From 1875-1887 she acted as assistant to the superior general, a position she had filled at various times. While recovering from a severe heart attack in February 1887, Sister Teresa decided to travel to Port Arthur (now Thunder Bay) to visit the congregation’s first northern mission to recuperate. She died there on August 23, 1887 at the age of fifty-six. Her funeral and burial took place in Toronto.
At the time of her death, the congregation had over 200 members caring for the sick and poor as well as teaching the young. Sister Teresa lived a life devoted to the needs of others and her efforts as a teacher and administrator created a foundation on which the Sisters would build institutions of teaching, health care and social work.