Markievicz took up arms with the Irish Citizen Army on 24 April 1916, helping occupy St Stephen's Green in the fight for Irish independence.
On 24 April 1916, Constance Markievicz, dressed in a modified Irish Citizen Army uniform and carrying a pistol, took part in the outbreak of the Easter Rising in Dublin. As second-in-command to Michael Mallin, she helped occupy St Stephen's Green and the College of Surgeons, directing the digging of trenches and the positioning of snipers.
The Rising was a pivotal armed insurrection by Irish republicans against British rule, and Markievicz's participation was extraordinary for a woman of her era and class — she was one of very few women to take an active combat role rather than a purely auxiliary one. Eyewitness accounts describe her calm command under fire and her willingness to shoot alongside male comrades.
Her involvement shattered contemporary assumptions about women's roles in armed conflict and nationalist politics. Though the Rising was militarily crushed within a week, it galvanised Irish public opinion against British rule, particularly after the harsh executions that followed. Markievicz's role became legendary, cementing her reputation as one of the most committed and visible women in the revolutionary movement, and paving the way for her later political prominence.