Margaret ('Madge') Daly was born on 4 February 1877 as the second of the ten children of Edward Daly and Catherine O'Mara. Her siblings included Kathleen Daly, Mayor of Dublin and wife of the Irish revolutionary Thomas Clarke; and Edward ('Ned') Daly, commandant of Dublin's 1st battalion of the Irish Volunteers during the Easter Rising and the youngest of the leaders executed in its aftermath. Margaret's father died in 1890, and six years later his brother, John Daly, assumed responsibility for the support of his widow and children. In May 1898 he established a bakery in Limerick city at 26 William Street, where several of his nieces worked.
When an auxiliary branch of the women’s nationalist organisation Cuman na mBan was established in Limerick on 5 June 1914, Margaret and her sisters became heavily involved in its activities. She was also actively involved in the planning of the Easter Rising. When her uncle died in 1916, Margaret inherited his bakery business and revealed herself to be an astute businesswoman. From the proceeds of the bakery she helped to support not only her sisters and their families but also the newly formed Volunteers. Her strong republican views subjected Margaret to repeated harassment by the military and the police, including the looting and burning of the bakery and the stopping of the bread van during delivery because of Gaelic lettering displayed on its side. Each time, she withstood the ordeal and successfully fought the authorities for compensation.
In the 1940s, Margaret relocated from Limerick to Dublin, where she died unmarried on 21 January 1969.