Born in Topanga, CA, Smart was raised with her younger brother, Adam, by her father, John, a salesman, and her mother, Judy, a museum worker. Though a shy girl growing up, Smart started to break out of her shell when she enrolled for ballet classes. She quickly realized that she loved the attention she received while dancing on stage. But her entry into show business came via modeling after childhood friend and future actress Vinessa Shaw suggested that Smart replace her on a photo shoot. Smart was hired and soon found herself traveling the world, doing shoots in places as varied as Italy, Tahiti and Mexico. Transitioning easily to acting, she made her onscreen debut in a "Rock the Vote" promo on MTV, which led to small parts in television movies like "Seduced by Madness: The Diana Borchardt Story" (NBC, 1996) and "Her Costly Affair" (NBC, 1996). Smart soon made her feature debit in Stephen Kay's "The Last Time I Committed Suicide" (1997), a biopic on beat generation icon Neal Cassady (Thomas Jane) which screened at that year's Sundance Film Festival.With her acting career starting to take off, Smart began landing higher profile features, including a role as a co-pilot in Paul Verhoeven's big-budget science fiction actioner "Starship Troopers" (1997), which she followed with an impressive turn in the quirky independent coming of age romantic comedy, "How to Make the Cruelest Month" (1998), playing Dot, the graceful golden girl who seduces the one-time boyfriend of her sister (Clea DuVall). Following the by-the-numbers horror film "Campfire Tales" (1998), she appeared in the topically chilling, but clumsily executed Internet stalker thriller "Dee Snider's StrangeLand" (1998), written, produced and starring the titular Twisted Sister singer, who played a deranged torturer who meets his victims in web chat rooms. Smart reached her widest audience with a co-starring role in Brian Robbins' surprise box office hit "Varsity Blues" (1999), in which she played Jules Harbor, a girl longing for life beyond her small town's high school football-obsessed culture but who remains forever attached to it as sister of the injured star quarterback (Paul Walker) and girlfriend of his idealistic replacement (James Van Der Beek). She would next be featured as Shawn Hatosy's upper-class love interest in Michael Corrente's poignant 1970s-era comedy "Outside Providence" (1999). Based on Peter Farrelly's novel, the film followed a working-class teenaged boy (Hatosy) sent by his abrasive but loving father (Alec Baldwin) to a tony prep school after running into trouble at home. Later that year, Smart joined the cast of "Felicity" (WB, 1998-2002), with a recurring turn as the new arrival who takes up with resident advisor Noel (Scott Foley) after the indecisive title character breaks his heart. Again playing off her somewhat retro looks, Smart next assumed one of the leading roles in the two-part miniseries "The 70s" (2000), playing one of four friends whose lives are transformed by the deadly shootings at Kent State in 1970. She received more mainstream exposure - literally, given a provocative topless scene - among youth audiences with her risqué, but sweet turn in the vulgar Tom Green campus comedy "Road Trip" (2000), playing a college girl who seduces a student (Breckin Meyer), only to have their tryst end up on a videotape inadvertently mailed to his girlfriend (Rachel Blanchard). Smart next played a 1970s hippie chick in "Scotland, Pa." (2001), writer-director Billy Morrissette's loopy version of "Macbeth" set amid fast food outlets and shag carpets. She next was one of the wacky ensemble in "Rat Race" (2001), paired again with Meyer as a beautiful helicopter pilot helping him seek out a $2 million prize, only to prove to be imbalanced when she launches a bizarre, jealous air assault on her boyfriend when she sees him frolicking in a pool with an ex. A large television audience became familiar with her during a multi-episode art on "Scrubs" (NBC/ABC, 2001-09), on which she played Jamie, the grieving young wife of a comatose man who becomes attracted to J.D. (Zack Braff). Meanwhile, Smart became a regular part of the second season of HBO's let's-make-a-movie series "Project Greenlight" in 2003, after she was cast in tyro filmmakers Kyle Rankin and Efram Potelle's movie "The Battle of Shaker Heights" (2003), playing the faraway object of a young man's affection. Smart was depicted as game and agreeable behind the scenes, though often flummoxed by the filmmakers' passive-aggressive and often hard-to-fathom directing style.Smart next starred in the uneven time-jumping thriller "The Butterfly Effect" (2004), playing the troubled childhood friend of a young man (Ashton Kutcher) who attempts to set things right, only to learn that changing the past will alter the future. After a small part as a nurse in the romantic comedy "Win A Date With Tad Hamilton!" (2004), Smart provided little more than mild titillation as a cheerleader in the wanting action-comedy "Starsky & Hutch" (2004). In the conspiracy thriller "Blind Horizon" (2004), she played a nurse drawn to a wounded man (Val Kilmer) found in the desert who claims to have knowledge of an assassination plot against the President of the United States. A small role in the barely seen sex comedy "National Lampoon's Barely Legal" (2005) was followed by a leading performance in the mainstream comedy, "Just Friends" (2005), in which she played the high school best friend of a shy and overweight teen (Ryan Reynolds) whose crush on her never went away, even after growing up to become a suave and successful music executive.Continuing to find meatier roles in the independent world, Smart appeared in the romantic comedy "Bigger Than the Sky" (2005), starring opposite John Corbett as a community theater actress playing Roxanne in a local production of "Cyrano de Bergerac." On "Smith" (CBS, 2006), her first regular television role, she was a master of disguise on a team of professional thieves led by a criminal (Ray Liotta) looking to make a few last scores before retiring. Unfortunately, the expensive series retired long before Liotta's character, lasting only three episodes after scoring poor ratings. After a supporting role in the indie drama "Peaceful Warrior" (2006), she starred in the high-octane thriller, "Crank" (2006), playing the girlfriend of a hit man (Jason Stratham) on the run from his vengeful former employers who injected him with a deadly poison. In the supernatural "Mirrors" (2008), Smart was the sister of a NYPD officer (Kiefer Sutherland) struggling with alcoholism and depression after his involvement in the death of an undercover officer, which she followed with a reprisal of her girlfriend role in "Crank 2: High Voltage" (2009); this time courted by both Statham and a mullet-sporting Corey Haim.