Maran's modeling career began at the age of 12; when an agent spotted her at a local barbecue restaurant, she began modeling part time. Maran graduated from the Castilleja School in Palo Alto, then began to pursue modeling more seriously. As those in the fashion industry consider her height of 5'7" to be too short for runway modeling, Maran works mainly in editorial modeling and advertising/image modeling.
Signed at age 17 with the Elite modeling agency of Los Angeles, Maran appeared on her first cover with Glamour magazine in 1998, and she was the featured Guess? Girl in their summer 1998 and fall 1998 campaigns. After building a resumé of over 25 commercials and advertisements, including playing Howie D's companion in the music video of Backstreet Boys hit Everybody (Backstreet's Back), in which she was bitten on the neck by Count Dracula (played by Howie D), Maran moved cross-country to join with Elite in New York City. In 1999, she landed a multi-year deal with Maybelline. Maran appeared in the annual Sports Illustrated Swimsuit Issue for three consecutive years; from 2000 to 2002. Maran is also signed with London agency Storm Model Management, and 1/One Management in New York City.
Josie's interest in the arts extends beyond film. When not in acting class, Josie is training herself in "dance classes... violin classes, speech classes, everything. I'm just trying to train myself in the arts, you know? Nobody else is gonna do it so I'm going to. I'm gonna take on the world". Her interest in music led her to play casually in two bands: Darling, with socialite Nicole Richie, and Hollywood 2000, where she sang and played violin.
In 2001, Maran appeared in an independent film, as title character Mallory in The Mallory Effect. In 2002, Maran appeared as Susan in Swatters. In 2004, she appeared in three films - as a French model in Little Black Book, as one of Dracula's brides in Van Helsing, and briefly as a cigarette girl in The Aviator. Maran appeared in a short film "The Confession" alongside Wentworth Miller in 2005, and as Kira Hayden in The Gravedancers in 2006. Maran will not play Polly Hudson in The Final Season, scheduled for release in 2007. This role is now played by Rachael Leigh Cook.
In 2005, she was recruited by EA Games to appear as a main character in the street-racing computer and video game, Need for Speed: Most Wanted, which was released on November 17, 2005. She plays the game's second lead Mia Townsend, who guides the lead character through the game.
In June 2007, Josie Maran launched her own natural cosmetics product line, named Josie Maran Cosmetics. Beyond her business activities she commits herself to the protection and improvement of nature and the environment.
On August 29, 2007 ABC announced Josie will compete on Dancing with the Stars. Josie and dance partner Alec Mazo took part in a chat session held at JosieAndAlec.com. They were the first couple eliminated from the show on September 26, 2007. Later that same night, Maran appeared on Jimmy Kimmel Live and in reference to getting voted off first, said, "I should have cut my legs off".