 In 2003, her father sent test photos to a Los Angeles office of IMG Models. By 2005 she was an up-and-coming model with the Marilyn NY agency. She did a 2005 fall campaign for Stella McCartney. By February 2006, she had been featured in each of the major editions of Vogue, including the cover of a Vogue Italia supplement. Following cover appearances for the October 2006 German Vogue and the July 2010 Italian Elle (she also later appeared on the October 2012 cover), she became one of the new faces of Guess clothing in late 2010. Miller has also done work for Victoria's Secret. Other ad work has included Bebe, Billabong, Chopard, Diesel, Elie Tahari, Intimissimi, Juicy Couture, La Perla and Laura Biagiotti.
