Zanetti began his competitive career in Italian junior categories. In 2003 he finished second in the Honda RS125 GP Trophy behind Luca Di Giuseppe, then claimed the title outright in 2004. Concurrently, he competed in the Italian 125 GP Championship, using those seasons to build the foundation for an international career.
In 2004 Zanetti made his debut in the 125cc World Championship, a series in which he would remain until the end of 2009. Those six seasons gave him extensive experience at the highest level of Grand Prix motorcycle racing, competing against future MotoGP stars in the intensely competitive entry-level class.
Following his stint in Grand Prix racing, Zanetti shifted toward production-based disciplines. In 2010 he finished second in the Italian Stock 600 Championship and made his debut in the FIM Superstock 1000 Cup. The Superstock series proved a better fit for his skills; in 2011 he achieved a strong second-place finish in the FIM Superstock 1000 Cup standings aboard a BMW S1000RR, establishing himself among the leading contenders in the class.
For 2012 Zanetti stepped up to the Superbike World Championship, the top tier of production-derived road racing, before moving across to the Supersport World Championship in 2013.
Zanetti's 2013 season in the Supersport World Championship was marked by a tragic event. On 21 July 2013, during a race held in Moscow, he was involved in an accident that resulted in the death of fellow competitor Andrea Antonelli. The incident cast a shadow over the remainder of the season and the Moscow Raceway round specifically, prompting reflection on safety standards at the circuit.
Despite the trauma of that race, Zanetti continued competing in the Supersport World Championship through 2014, 2015, and 2016, demonstrating considerable resilience and commitment to his career. His consistency across those seasons made him a familiar name in the paddock over more than a decade of international racing.
In the years following his Supersport World Championship tenure, Zanetti returned to Italian domestic competition, racing in the CIV Superbike Championship aboard a Ducati 1199 Panigale. He also competed in MotoAmerica, the premier American superbike series, at various points in his career, illustrating the breadth of his racing activities across different markets and championships.
The Brescia-born racer's career trajectory — from Honda RS125 trophies through the 125cc World Championship and into Superstock, Superbike, and Supersport World Championship competition — reflects the typical pathway of Italian motorcycle racing talent, grounded in the deeply competitive domestic Italian scene before earning international recognition.
Zanetti represents a generation of Italian motorcycle racers who competed internationally across multiple eras and disciplines of road racing. His career spanned from 125cc Grand Prix competition to the flagship Superbike World Championship, encompassing nearly every major production-based international series along the way. Though he never claimed a world championship title, his longevity and adaptability across different machinery and formats underline a professional career of considerable scope.