Power is born Jane O’Toole in Baltinglass, County Wicklow on May 1, 1858. In the 1880s she joins the Ladies’ Land League and finds herself immersed in their activities during the Land War. She compiles lists of those evicted from their homes and also organises the Land League in Wicklow and Carlow. In 1883 she marries John Wyse Power, a journalist who shares her political beliefs and is a member of the Irish Republican Brotherhood (IRB). They have four children together, a fact that does not interfere with her political work.
Power helps set up the Irish Women’s Franchise League and is also a founding member of Inghinidhe na hÉireann and Sinn Féin becoming Vice-President of both organisations. She is later on the Provisional Committee that sets up Cumann na mBan. She rises in the ranks to become one of the most important women of the revolution. In October 1914, she is elected the first President of Cumann na mBan. She is a successful business woman owning four branches of her Irish Farm Produce Company. The 1916 Proclamation of the Irish Republic is written in her home at 21 Henry Street, and she always maintains that the Military Council signed the proclamation in no particular order; they just signed as it was passed to each of the signatories, though, with James Connolly being eager to be the first to sign. Even the identity of the head of the Provisional Government was not altogether clear.
During the 1916 Easter Rising she supplies food to the Irish Volunteers. After the Rising she and her daughter, Nancy, help re-organise Cumann na mBan and distribute funds to families suffering hardships, as well as the Prisoners Dependants Fund. These funds had been sent by Clan na Gael in the United States. She is subsequently elected as one of five women members onto Dublin Corporation in 1920 for the Inns Quay – Rotunda District.
Power supports the Anglo-Irish Treaty and by the end of 1921, she is convinced that in doing so, will mean the need to leave Cumann na mBan to form a separate organisation. She helps set up Cumann na Saoirse (The League for Freedom), the pro-Treaty women’s organisation and becomes its Vice-President. She is a Free State Senator from 1922 until 1936 and is also a member of Cumann na nGaedhal.
Jennie Wyse Power dies on January 5, 1941, aged 82, at her home in Dublin. She is interred in Glasnevin Cemetery with her husband and daughter, Máire (who predeceased her). Her funeral is attended by many from both sides of the Dáil and the former revolutionary movement.