A member of Cumann na mBan and the honorary secretary of the executive committee, she took part in the 1916 Easter Rising and the War of Independence.

She was educated in both the Loreto Abbey in Gorey and Dublin and attended boarding school in Thurles called The Ursuline.

After leaving secondary-level education, she attended the Royal University of Ireland, taking English, German and French.

She was a very attractive woman with a strong interest in current affairs although not with a great insight into the subtleties of politics and the struggle for national independence.

[1][2][4] Early in the morning before Seán Mac Diarmada was executed, she outlined her visit in an article with her sister Phyllis to him.

Ryan was present at the house where some of the leaders of the planned insurrection met and it was decided, by them, to call off the event for Easter 1916.

She delivered the message but hoping that in fact the rising would still take place she told the men in Wexford her opinion and returned to Dublin to see what would happen.

Despite being involved with one of the leaders of the Rising, Ryan was unaware of the plans, only that she could tell something was to happen and that her fiancée was extremely busy and stressed.

She had returned home when a sniper had shot a dog in front of her while she was headed back to the GPO and passing the College of Surgeons.

She and Louise Gavan Duffy went to Jacob's Factory on the Sunday morning to witness the final surrender of the men there.

[8] During the Irish War of Independence, Mulcahy spend a significant amount of time on the run, and the family lived in the old buildings used by Pearce for St Enda's School.

Eventually, his mother asked them to leave since the frequent Black and Tan raids on them caused damage to the house.

She worked alongside her sister Phyllis for the Army Benevolent Fund, even though they had been on opposite sides during the war.

[3] Mr and Mrs Mulcahy were remembered by their children as a loving couple, but that may not have been visible to the public eye.

[clarification needed][8] In June 2020, a newly constructed public park in her home county of Wexford was named in her honour.