On 21 January 1919, Markievicz became the first woman to sit as a member of the newly convened Dáil Éireann, Ireland's revolutionary parliament.
On 21 January 1919, elected Sinn Féin MPs, refusing to recognise British authority, convened instead as Dáil Éireann, a unilaterally declared revolutionary parliament of the Irish Republic, meeting for the first time at the Mansion House in Dublin. Constance Markievicz, elected for Dublin St Patrick's, attended as one of the assembly's members, becoming the first woman elected to and seated in Dáil Éireann.
This inaugural sitting of the First Dáil was a defining act of the Irish War of Independence, asserting Irish sovereignty by adopting a Declaration of Independence, a Democratic Programme, and a message to the free nations of the world. Markievicz's presence at this historic session, unlike her non-attendance at Westminster, marked her practical entry into functioning parliamentary politics — but on Irish revolutionary terms.
Her position as the sole woman among the Dáil's founding members was a powerful statement about the role women could play in the new Irish state being envisioned. It set a precedent for female participation in Irish republican governance and foreshadowed her appointment to ministerial office just months later. Her legacy as the first female TD remains a touchstone in Irish political history, commemorated at the centenary of the Dáil in 2019.