Benz was born in Pittsburgh, Pennsylvania. Her father is a Pittsburgh surgeon and, contrary to rumor, her mother was never an ice figure skater. The family settled in nearby Murrysville when Benz was two, and she started ice skating when she was three. She competed in the 1988 U.S. Championships in junior ice dancing with her partner David Schilling, coming in 13th. Her older brother and sister, Jeffrey and Jennifer, were the 1987 U.S. Junior Champions in ice dancing and competed internationally. When Benz was 14, she had a bad stress fracture and had to take time off. She grew up in Murrysville, Pennsylvania, graduating from Franklin Regional High School. She later graduated from New York University.

After graduating from high school, Julie entered New York University to study acting. After graduation, Julie moved to Los Angeles to further pursue her career and landed some small roles in movies and TV shows, including a guest appearance on an episode of Married with Children in 1994 and a role in the Aaron Spelling unaired TV pilot Cross Town Traffic. She also starred as Christie Lambert in another unaired TV pilot called Empire in 1995. She went on to guest star in many TV shows which include Hang Time, High Tide, Step by Step and Boy Meets World. She also had a small role in the TV movie The Barefoot Executive. She had an uncredited role in Black Sheep and guest appearances in the shows Diagnosis Murder, Sliders and The Single Guy. She played Kristy in the TV movie Hearts Adrift and a lead role as Julie Falcon in Darkdrive.

Julie then guest starred on popular shows like Supernatural, CSI: Miami, Law & Order and CSI: Crime Scene Investigation. She had a supporting role in a Swedish independent movie called Kill Your Darlings, a lead role in the Lifetime Movie Circle of Friends and joined the main cast of TV show Dexter as Rita Bennett. She plays the lead female Sarah in Rambo and then appeared in a promo campaign for PETA called Violence Link PETA PSA and a promo for the Burma: It Can't Wait Campaign. She is also going to be the lead role in the fifth film of the popular Saw franchise, Saw V playing a character called Brit. She has a lead role in the sequel The Punisher: War Zone as Angela Donatelli.