Rosanna Diane Davison commenced her pageantry journey with vying for the crown of Miss Ireland 2003 which resulted in her victory at the end of the event. She then represented Ireland in Miss World 2003, held in Sanya, China. After surpassing 106 candidates from different countries, Davison became the winner of Miss World 2003 marking herself to be the first Irish participant to do so. During her reign, she traveled to different countries including United Kingdom, United States, Canada, China, and Sri Lanka. Rosanna follows a vegan diet and is a strong supporter of PETA. In August 2015, she published her first cookbook, Eat Yourself Beautiful which turned out to be a best-seller.