Pressly was born in Kinston, North Carolina to James Liston Pressly (a car salesman) and Brenda Sue Smith (a classical dance instructor); she has a sister, Jessie and a brother, Jim. Pressly spent 11 years studying gymnastics and dancing.

By the time she was 14, she was already the spokesperson for her modeling agency, "International Cover Model Search" and had begun to gain recognition for modeling in the United States, as well as in Italy and Japan. Pressly attended Costa Mesa High School in California, where she lived with her mother while her parents were in the process of a divorce. She subsequently had herself legally emancipated from her parents at the age of 15.

One persistent rumor is that Pressly married a man named Brodie Mitchell in 1998. Pressly, who has never married, has stated she has heard of Mitchell but does not know him. Mitchell apparently has made enough claims about being married to Pressly that some sources have reported it as fact.

Pressly dated her Jack and Jill co-star Simon Rex in 2000 and 2001. In a December, 2001 interview with Howard Stern (the same notorious interview in which she accounted for Stern's not-so-handsome looks by saying that he got "slapped [with] a yarmulke" at birth), she claimed that Rex "dumped me on my birthday." She was later linked to Carson Daly, and in 2004 Kid Rock confirmed he was dating her(they broke up shortly afterwards).

Pressly worked as actress Drew Barrymore's body double in the film Poison Ivy. She starred in the 1997 sequel, Poison Ivy: The New Seduction. In 1999, Pressly was cast as the promiscuous dancer "Audrey" on the television show Jack and Jill.

Pressly starred in the independent film Poor White Trash, playing scheming gold-digger Sandy Lake. She subsequently appeared in a number of widely released films, including Not Another Teen Movie (playing a stereotypical high school cheerleader) and Torque, as a crazed motorcycle-riding criminal.

In 2001 she was made the new spokesmodel for Liz Claiborne Cosmetics and its fragrance Lucky You. Pressly has posed nude for the March 1998 and February 2004 issues of Playboy and has performed with The Pussycat Dolls. In 2002, she was ranked #8 in Stuff magazine's "102 Sexiest Women in the World". In 2003, she launched a lingerie line, J'Aime, which has now become a full sleepwear and ready-to-wear line. In 2006, Maxim magazine named her #34 on their annual Hot 100 list; she is also featured in their Girls of Maxim gallery.

She also appeared in a number of music videos, including Girls of Summer by Aerosmith and a cover of Tainted Love by Marilyn Manson.

In 2003, Pressly was an honorary captain for the Carolina League in the California-Carolina League All-Star game in Rancho Cucamonga, California. Her hometown team, the Kinston Indians, is a member of the Carolina League.