Jill Hennessy is a Canadian actress and musician.

In 1988, Jill Hennessy landed a role in the film Dead Ringers. In 1990, she appeared on Broadway in the musical Buddy - The Buddy Holly Story.

She played Dr. Marie Lazarus in RoboCop 3 in 1993. That same year, she landed the role of assistant district attorney Claire Kincaid in the NBC crime drama Law & Order.

In 1999, she played Lisa in Chutney Popcorn. A year later, Hennessy wrote, produced, and co-directed an independent film, The Acting Class.

In 2001, she portrayed Jackie Kennedy in the film Jackie, Ethel, Joan: The Women of Camelot. She had a cameo appearance in the film Abby Singer.

Aside from being an actress, Hennessy recorded an album, Ghost in My Head, in 2009. She was one of the performers in Lilith Fair in 2010. She was an endorser of Zaxby's "Zalads," and made a pair of television commercials in 2012.

Jillian Noel Hennessy was born on November 25, 1968 in Edmonton, Alberta, Canada. She graduated from Grand River Collegiate Institute in Kitchener, Ontario. She is married to Paolo Mastropietro and has two sons.