[3] In 1999, Ní Chuilín was one of two founding directors of Coiste na nIarchimí, a company described as "the umbrella organisation for republican ex-prisoner self-help groups throughout Ireland".

[8] Ní Chuilín has been active with Sinn Féin since her release from prison and represented the Oldpark electoral area on Belfast City Council from 2005 to 2007, when she was replaced by Conor Maskey following her election to the Northern Ireland Assembly.

In this capacity Ní Chuilín became the first senior Sinn Féin representative to attend an association football match involving the Northern Ireland team, when it defeated the Faroe Islands at Windsor Park on 10 August 2011, but she did not attend until after the playing of the Northern Ireland Anthem of "God Save The Queen", and she commended "the very real efforts that have been made by the IFA to tackle sectarianism at their matches".

[10] In September 2011 Ní Chulín's Department launched Líofa 2015, a project aimed at encouraging people in Northern Ireland to learn, teach and speak Irish.

Among those taking up the challenge to achieve conversational fluency by 2015 was Judith Gillespie, Deputy Chief Constable of the Police Service of Northern Ireland, and some 1509 other PSNI officers.