Karen Young was born in Pequonnock, New Jersey, and educated at Rutgers, the state university. The eldest of six children, her mother was a homemaker, and her father was a stone mason. After college, she came to New York City to pursue a career in acting, and has been a New Yorker ever since.

One of her first successes was in the original theatrical production of "A Lie of the Mind", written and directed by Sam Shepard. She has consistently worked in film, most recently in the French production of 'Vers le sud (2005)' , starring opposite Charlotte Rampling. It was directed by the esteemed director Laurent Cantet in both Haiti and the Dominican Republic. Viewers can also see her as FBI Agent Robyn in the HBO series, The Sopranos.
Appears with her ex-husband, Tom Noonan, in the movie The Wife, for which he was also the writer.