Dunne was born in County Dublin and raised in County Mayo, Ireland. She trained at the Gaiety School of Acting before beginning her professional career in 2009.She made her acting and writing debut in the television film Dublin Stories and appeared in two episodes of Rental Boys. In 2010, she co-wrote and appeared in The Taste of Home. In 2014, she wrote and starred in the RTÉ One comedy The Walshes as Carmel Walsh.