Hennessy was born in Edmonton, Alberta. Her father, John Hennessy, was a meat salesman, a job that required considerable travel and resulted in frequent moves for the family. Her mother, Maxine, left the family in 1982, leaving her daughter to be partially raised by her paternal grandmother, Eleanor, in Kitchener, Ontario. She has a younger brother, John Hennessy Jr., and an identical twin sister, Read more...

Hennessy and her sister played twin call girls in 1988's Dead Ringers. She was short-listed for the role of Dana Scully, on The X-Files. Hennessy is famous for playing Claire Kincaid on Law & Order (1993 – 1996) and the lead role as Jordan Cavanaugh on Crossing Jordan. In 1999 she played Lisa in Chutney Popcorn. In 2000, Hennessy wrote, produced, and co-directed with Elizabeth Holder Read more...

Hennessy is multi-lingual, and speaks Italian, French, Spanish and German. She married Paolo Mastropietro, a former bartender and sometime actor, on October 1, 2000. Her husband opened a tavern in Northvale, New Jersey, in 1999, and named it Hennessy Tavern, after his wife. The tavern is located next to the former bowling alley where the television series Ed was filmed. Hennessy also enjoys riding Read more...