 Mulgrew was born in 1955 in Dubuque, Iowa, into an Irish American Catholic family, to Thomas James "T.J." Mulgrew II, a contractor, and Joan Virginia Mulgrew (née Kiernan), an artist and painter.She attended Wahlert High School in Dubuque.At age 17, she was accepted at the Stella Adler Conservatory of Acting in New York, conjoined with New York University in New York City.