When Simpson first broke onto the music scene in 2004, she was set apart from her sister's already established image by a different musical style, different fashion choices, and a more assertive personality. Simpson's songs have been characterized by

When Simpson first broke onto the music scene in 2004, she was set apart from her sister's already established image by a different musical style, different fashion choices, and a more assertive personality. Simpson's songs have been characterized by rock elements absent from her sister's music, and, particularly during the time of her initial stardom, Simpson would often wear outfits highlighting a more rock or punk-influenced sense of style. Her fingernails and toenails have often been painted black. Over time, Simpson has moved toward more typically feminine styles. In March 2008, she said that "I like to get dressed up now, and that's something I've never been into before" and "I like to be feminine and sexy." According to Simpson, in her sense of style she tends to "mix and match".

Previously blonde like Jessica, she dyed her hair dark during the recording of the MTV reality show after she finished filming for the 7th Heaven television series. In November 2004, she debute