Mathieu was editor of a major online portal for several years before joining Éditions Nivéales, France's largest action sports media company: Éditions Nivéales publishes magazines such as Snowsurf, Ski Magazine, Skieur Magazine, Grimper, Montagnes, and Vertical. Although he started snowboarding relatively late at the age of 15, Mathieu has tested more than 500 different skis and snowboards in the past 20 years.