Hilary was born in New York City, New York. In the late 1980s, Shepard was a lead singer and percussionist in the short-lived all-girl group American Girls.
When that group ended, she moved into acting, appearing in numerous motion picture and television series. Shepard is best known for playing the character of the evil pirate queen, Divatox, in Turbo: A Power Rangers Movie. During the first half of the TV series Power Rangers Turbo, Shepard was replaced by actress Carol Hoyt in the role of Divatox as she was on maternity leave but returned to the role during the latter half of the series.
She also had two roles on Star Trek: Deep Space Nine: the Benzite ensign Hoya and Lauren, one of the genetically enhanced humans.
She played Zena in the film Scanner Cop.
Shepard and actress Daryl Hannah co-created two board games, “Love It or Hate It” and “LIEbrary,” the latter having been previewed by Hannah on The Ellen DeGeneres Show in December 2005.
Most recently, Hilary has been seen in several TV movies including A Husband for Christmas and The Wrong Roommate.
In 2017, she will star in the upcoming short film The Order.