She then starred in the blockbuster film The Day After Tomorrow (2004) and The Phantom of the Opera (2004) for which she was nominated for a Golden Globe.
She has since starred in Poseidon (2006), Dragonball: Evolution (2009) and Dare (2009). Rossum has since joined the cast of the Showtime television drama series Shameless in a leading role. The series, which stars William H. Macy, premiered in January 2011.
Rossum was born in New York City, New York,the only child of Cheryl, a single mother who worked as a corporate photographer and an investment banker. She was named after her grandfather, whose first name was Emanuel, using the feminine spelling Emmanuelle.Rossum was raised by her mother and has only met her father twice. She is the niece of Vera Wang, to whom she is related by marriage. Her mother is Jewish and her father is "a WASP".Rossum's parents divorced before she was born.
Upon singing "Happy Birthday" in all 12 keys, Rossum was welcomed to join the Metropolitan Opera Children's Chorus by chorus director Elena Doria at the age of 7. Over the course of five years, she sang onstage with the chorus and had the chance to perform with other opera greats, such as Plácido Domingo and Luciano Pavarotti.
For $5–10 a night, Rossum sang in six different languages, in 20 different operas, including La bohème, Turandot, a Carnegie Hall presentation of La damnation de Faust and A Midsummer Night's Dream. She also worked under the direction of Franco Zeffirelli in Carmen. Rossum joked in interviews that her vocal talent and affinity for music developed because her mother always listened to classical music and operas while she was pregnant with her.
By age 12, Rossum had grown too big for the children's costumes. An increasing interest in pursuing acting led to taking classes with Flo Salant Greenberg of The New Actors Workshop in New York City. She also hired an agent and auditioned for many acting roles.
Rossum attended the Spence School, a private school in Manhattan, for a year before dropping out to pursue career opportunities. She received her high school diploma at 15 years old via online extension courses offered by Stanford University's Education Program for Gifted Youth (EPGY) She currently attends Columbia University.
Rossum has celiac disease, an autoimmune disease in which the body can't tolerate any foods containing gluten or wheat. She revealed her condition on MTV News after being given a cupcake on-camera to celebrate her 22nd birthday; she was only able to eat the frosting. One of her best friends is actress Leighton Meester, a member of the Gossip Girl cast.
Rossum was married to music executive Justin Siegel for a year and a half before he filed for divorce on September 25, 2009. Rossum began dating Counting Crows frontman Adam Duritz after touring with the band in the summer of 2009.They broke up in September 2010.