Jenney was born in Long Island City, Queens, New York. She began her acting career in 1979 with the film Impostors. Several roles followed throughout the eighties, with appearances in the 1986 comedy The Whoopee Boys, and the award-winning Peggy Sue Got Married, with Kathleen Turner and Nicolas Cage. She appeared as ‘Iris’ in the Oscar-winning film Rain Man, starring Dustin Hoffman and Tom Cruise. In 1991, Jenney played waitress ‘Lena’ in Ridley Scott’s Thelma & Louise; the following year, she appeared in American Heart, a film which earned her an Independent Spirit Award for Best Supporting Female.
Jenney has had a successful career in television. Several of her television credits include guest roles in Miami Vice, The Practice, Judging Amy, The West Wing, 24, Law & Order, its spin-offs Law & Order: Criminal Intent and Law & Order: LA, Crossing Jordan, Six Feet Under, House, CSI: Crime Scene Investigation, ER, Monk, and portrayed Admiral Adama’s wife, Carolanne on Battlestar Galactica, in the episode “A Day in the Life”.
Jenney has appeared in many television films throughout her career. Her first was Out of the Darkness, with Martin Sheen. Some of her roles include Shoot First: A Cop’s Vengeance, The Habitation of Dragons, A Stranger in Town, First Time Felon, the Emmy Award-winning If These Walls Could Talk 2, and The Pennsylvania Miners’ Story.