Born March 6, 1968 in Queens, New York, she is the third of six kids. Her father, Peter, was trained as a concert violinist. Her mother, Anne, is a nurse. Both are Irish immigrants. Moira was raised in Ronkonkoma, NY. She attended Connetquot Senior High School and graduated in the class of 1986. Later Moira attended Marymount Manhattan College. In 1984 Moira was cast in a small role in Connetquot Senior High School's production of Annie. Due to illness, the young woman playing Miss Hannigan was replaced, causing a series of cast changes. Director Eric Martinsen chose to recast Moira as Grace Farrell. She was a great success, and so began her career.