On August 14, 2004, Gercke won a casting call for fast food chain Burger King. She was represented by Langer-Pueschel who booked her for photoshoots, catwalk shows, and dance performances. At the beginning of 2006, she attended a casting call for Germany’s Next Topmodel hosted by Heidi Klum. Upon winning the competition, she received an advertising contract with the fashion label OuiSet, a modeling contract with IMG Models in Paris, the cover shoot for the June 2006 issue of German Cosmopolitan and an advertising contract with Microsoft for Windows Live. She also appeared in magazines such as the American issues of Cosmopolitan, Sports Week, Glamour and on the cover of French Votre Beauté. She was featured in print campaigns of H&M, Mexx and Geox. In 2010 she walked on New York Fashion Week for the Spring season of Custo Barcelona.