Mary Frances O'Connor was born on August 9, 1890 in Leam West, Oughterard, County Galway, Ireland. Her parents were Patrick O'Connor and Mary Connelly.

Hospital Nurse, Mary O'Connor, 40, was a lodger at a home on Fisk Street, Pittsburgh, when the 1930 census was enumerated in April 1930. The record erroneously states that she immigrated in 1900 and was a Naturalized Citizen. Four other nurses, all St. Francis graduates, were also lodgers in the home: Magdalen Abt, Class of 1923; Mary (Marie) Gabriel, Class of 1923; Anna O'Brien, Class of 1929, and Ruth Frederick, Class of 1929.

Mary was struck by an auto in 1937.

In 1940, Mary, stated age 44, lived with the family of her sister, Catherine Naughton, on Hulton Street, Carnegie. Her occupation was "Nurse, Institution," and family histories indicate she worked at Kane Hospital, Scott Township.

From a list of Pennsylvania Registered Nurses, 1940-1941, published by the Pennsylvania State Board of Nurse Examiners: "Mary Frances O’Connor, 511 Hulton St., Carnegie."

According to family records, Mary became a Naturalized Citizen on April 30, 1942.

Mary O'Connor, a resident of Carnegie, Allegheny County, died at St. Francis Hospital on July 25, 1959. She is buried at Mt. Olivet Cemetery, Heidelberg, Scott Township, Allegheny County.