 She, in time, became the fifth woman to be an Irish barrister.Born to James and Elizabeth Duggan in Kilbeggan, she was christened Marion Elizabeth Duggan in St. Mark's Church, Dublin..Her father was a sub agent for the Bank of Ireland, as a result they moved around living in Rossleaghan, Borris in 1901 and Ranelagh in 1911..

Duggan was the third woman graduate of Law, getting her degree in 1910 from Trinity College Dublin and a prominent suffragist in Dublin.