Born in Florida, Lenz moved to Texas at age 4. She landed her first role at 7 as a Munchkin in an adaptation of The Wizard of Oz and by age 10 she had been cast in the role of Scout in To Kill a Mockingbird at the Irving Community Theater in Texas. While on a class trip to Los Angeles, Lenz landed her first professional job in a commercial for Swans Crossing, a teen series.

Lenz loved to perform, and in 1992 her family moved again, this time to New Jersey, which enabled her to pursue acting in New York City. She began auditioning and booked several commercials, including Eggos Waffles and Dr. Pepper. In her sophomore year of high school, Lenz's talent caught the eye of a casting director. Joy was hired to play Linda Halleck in the Stephen King thriller Thinner.

In March of 1998, she landed a nine-episode stint on the daytime drama Guiding Light as Reva Shayne's teenaged clone. Lenz's performance as the spunky and vulnerable clone earned her raves from viewers and critics alike. Soon after she was offered a contract role playing Michelle Bauer, the proverbial girl next door. In 1999, while still appearing on the show, she won the role of Rose Cronin in Mary and Rhoda, playing the daughter of Mary Tyler Moore's character in the TV movie based on the popular 1970s TV show.

After two successful years on the soap opera, Lenz headed to the West Coast and immediately booked a guest spot on The WB comedy Off Centre. She followed that up with guest roles on Felicity, Maybe It's Me, Charmed, The Guardian and the pilot Destiny for Jerry Bruckheimer Productions.

Lenz is also an incredible singer, with a four-octave vocal range. She has worked with director Garry Marshall and Carole King on a new musical and with director Arthur Allan Seidelman on a production of The Outsiders.

She can next be seen as Marni in the feature Bring It On, Again, a sequel to the Universal feature.

Lenz likes to spend her free time with her family and friends. She enjoys horseback riding, playing piano and guitar and writing new music.