Kathleen O'Connell was born Catherine O'Connell at Caherdaniel, County Kerry on 5 October 1888. She was one of eleven children of farmer John O'Connell and Mary Ann O'Connell (née O'Sullivan). She was educated in County Kerry, and emigrated to Chicago in 1904 where she trained to be a secretary. She left a well-paid commercial job in 1912 to become secretary to the American delegation of the Gaelic League in New York. She worked closely with Thomas Ashe and Diarmuid Lynch on fund-raising and handled their secret IRB correspondence. She returned to Ireland briefly in 1915 to attend the Gaelic League oireachtas and ard fheis, voting in favour of the politicisation of the organisation. During the same visit she brought money and messages to the Irish Volunteers from John Devoy. O'Connell attended the New York Irish Race Convention, going on to work of the Friends of Irish Freedom. In this position she organised and collected for the "victory fund" for Irish independence. She was also a typist for Clann na Gael. After the Easter 1916 Rising, she became a member of Cumann na mBan in the US, raising money for the widows and children of those killed or wounded during the Rising. It was through this work that she became a close friend of Arthur Griffith and his family.