McCarthy has been a councillor on Dún Laoghaire Rathdown County Council since 2004. She is a former chairperson of the Dublin Regional Authority. She is a founding member of the Stepaside residents' association and the Stepaside Tidy Towns. She works part time as a specialist dental nurse in Donnybrook.

I hope people will look at my track record on Dún Laoghaire-Rathdown Council. Having spent years on the outside involved in Tidy Towns, I became an activist and at a certain point, I realised I could do more on the inside of the council.

My first priority has always been to improve the quality of life for all, especially by improving the physical and natural environment in which we live.

I want to end the cruelty imposed on families who have children with a disability or a mental health-related illness and who are at wits end fighting for services or even just respite care. I will be their voice in Dáil Éireann.