Harden, one of five children, was born in La Jolla, California, the daughter of Texas natives Beverly (née Bushfield), a housewife, and Thad Harold Harden (1932–2002), who was an officer in the United States Navy. One of Harden's brothers is named Thaddeus, as is her former husband. Harden's family frequently moved because of her father's job, living in Japan, Germany, Greece, California, and Maryland. She graduated from Surrattsville High School in Clinton, Maryland, in 1976, the University of Texas at Austin with a BA in theatre, and the Graduate Acting Program at New York University's Tisch School of the Arts with a Master of Fine Arts.