After moving back to Manhattan, Gastineau signed with the Elite Model Management, and became a model as part of their celebrity division. Within weeks of signing with the agency, she appeared in a spread for "Stuff" magazine. She walked runways for Anne Bowen and Anna Sui during NYC fashion week in 2005, and signed an endorsement deal with L'Oréal Paris, which led to a European advertising campaign. During that time, she became the face of casual wear designer Ed Hardy. Later, Gastineau appeared on the cover of "Steppin' Out", "Hamptons" and "Lucire" magazines. In 2005, she appeared on "Maxim" magazine's Hot 100 list, ranking at number 60.