Born Sept. 12, 1986 in NYC, to her banker father and her corporate photographer mother. Rossum developed a passion for music at the tender age of seven when she was chosen to join the Metropolitan Opera at Lincoln Center as part of the Children’s Chorus. It was here that she collaborated with the likes of such musical talents as Dimitri Hvorostovsky and Denyce Graves and made her singing debut in Tschaikovsky’s 1995 production of “Queen of Spades.” Rossum went on to appear in 20 different operas, including Tim Albery’s production of Benjamin Britten’s “A Midsummer Night’s Dream,” and had the chance to perform at Carnegie Hall in 1997 in a presentation of Berlioz’s “La Damnation de Faust.” Trained in stagecraft and classical vocal technique, Rossum developed a keen sense for language and dialect while at the Met, which helped catapult her to a later career in TV and film. Unfortunately, the teen was enrolled at the prestigious all-girl Spence School in Manhattan, until administrators, upset with her frequent absences, delivered an ultimatum - forego all career opportunities in order to concentrate on schoolwork, or withdraw. She opted for the latter, leaving to pursue her acting career, and later graduated from high school after completing "virtual classes" sponsored online by Stanford University.

Rossum made her first TV appearance at age 11 as Abigail Williams on the longtime running daytime soap, “As the World Turns” and went on to make guest appearances on the highly-acclaimed dramas “Law and Order,” (NBC, 1990- ) in 1997 and “The Practice” (ABC, 1997) in 2001. Her short, yet notable stints in episodic television opened doors to TV films, where she starred in “Genius” (Disney Channel, 1999) and charmed viewers and critics with her portrayal of the teenage Audrey Hepburn in the ABC Original Movie “The Audrey Hepburn Story” (2000).

It wasn’t long before big-screen Hollywood came knocking. Rossum ventured into less conventional roles with her film debut as an Appalachian orphan in the 2000 indie feature, “Songcatcher.” The movie won the Special Grand Jury Prize for Outstanding Ensemble Performance at the Sundance Film Festival and her performance earned the youngster an Independent Spirit Award nomination in the category of Best Debut Performance. But her mainstream break came when she scored the supporting role of Sean Penn’s murdered daughter in the 2003 critically acclaimed “Mystic River.” Rossum segued easily from the Clint Eastwood-directed character piece to the special effects-laden, adrenaline-infused film, “The Day After Tomorrow” (2004). In the apocalyptic hit, Rossum played Jake Gyllenhaal's love interest – both young students trapped in NYC amidst disastrous global warming.

Rossum had garnered enough praise as the “next big thing,” that filmmaker Joel Schumacher and others involved could not help but take notice when casting his dream project – the highly anticipated film adaptation of Andrew Lloyd Webber's "Phantom of the Opera" (2004). The stage musical’s creator, Sir Andrew Lloyd Webber, personally selected Rossum, who was only 16 at the time, to star as the beautiful opera singer who becomes the object of the Phantom’s obsession. Rossum equated herself marvelously in a winning performance that seemed beyond her years, providing the best moments in the entertaining but somewhat uneven adaptation. At 18, she received her first Golden Globe nomination for Best Performance by an Actress in a Musical or Comedy for the film, along with the National Board of Review’s award for Best Female Breakthrough Performance of 2004 and the Broadcast Film Critics’ Association Award for Best Young Actress of 2004.

After the "Phantom" media blitz subsided, Rossum returned to the big budget blockbuster, appearing with an all-star cast in Wolfgang Petersen's summer flick, "Poseidon" (2006). At the same time she was trying to survive an overturned cruise ship, Rossum began recording an album of pop music for Geffen Records.