[2] Donnelly first became involved in political activity in 1955 when she campaigned [citation needed] for the Sinn Féin candidate Tom Mitchell in the Mid Ulster constituency for that years Westminster election,[3] and in the re-run of that election after Mitchell was barred from being a candidate because he was imprisoned in Crumlin Road Gaol for a failed IRA raid in Omagh, County Tyrone at the time.
[6][7] As a prominent member of the NICRA, she was present at Bloody Sunday in January 1972 when soldiers opened fire at civil rights demonstrators, with 14 ultimately being killed.
That years election demonstrated the level of support Democratic Left had taken in its split from the party nationwide, with Pat McCartan outperforming Donnelly by over 3,000 votes.
[9][13] She and James McLaughlin were both selected as Workers' Party candidates to run in the East Londonderry constituency for the 1996 Northern Ireland Forum election.
[15] In December 2018, she delivered the eulogy at the funeral of former leader of the Workers' Party, and veteran Official IRA member, Seán Garland.