Marloes Horst began her career in the fashion world in 2007 thanks to a contract with modeling agency IMG Paris, by which she was photographed by Valerie Phillipa for the British edition of Elle and in June was chosen as a model of the week from the site models.com. There followed covers for Grace, D - The Republic of Women and Elle and a new contract with NEXT Model Management.
In September 2008, she debuted on the Milan catwalks of Prada. Following this Horst has also worked with Goldenpoint, Liu Jo, Massimo Rebecchi and Nando Muzi, and has appeared in magazines such as Vogue Russia, L'Officiel and Velvet. She was also chosen as one of the protagonists of the 2010 Pirelli calendar, photographed by Terry Richardson.