Katy Louise Saunders was born as a daughter of a British father and a Colombian mother in London. However, she came to Italy as a child, where she has lived in Rome since then and completed the English school there. Even before her career as an actress, she studied economics at the University of Economics Luigi Bocconi in Milan.
Her film career began in 2002 when she took on a secondary role in Michele Placido’s film Un viaggio chiamato amore. Only a year later, in 2003, she stood next to Hilary Duff in the film The Lizzie McGuire Movie. In Los Borgia a film drama from 2006, Saunders was called Giulia Farnese, the beloved of Pope Alexander VI. In 2007 she played alongside Hayden Christensen, Mischa Barton and Tim Roth, in the film Virgin Territory. As in Decameron, ten young Florentines seek refuge from the plague on a castle. However, contrary to the literary origin of the Middle Ages, which is limited to the narration of stories, the protagonists of the film have a desire for adventures, raucous jokes, romance and swords. In 2009 she appeared in Sisi, a film about the well-known Austrian Empress as her Hungarian court maid Ida Ferenczy. Furthermore, in 2010, she embodied the role of Lucilla, the niece of Augustine in the film The Life of Saint Augustine, which is portrayed by Franco Nero.
In addition to her career as an actress, Saunders also proved to be a model, including the Foundation for AIDS Research (amfAR). In 2008 she was on the side of George Clooney in a commercial for the coffee brand Nespresso.