Zanarini was born in Bologna, Italy. He began his career in the motorsport industry as a marketing director for Alfa Romeo, covering Australia and the South Pacific region. The role gave him an early grounding in the commercial side of motor racing, and in 1986 he relocated his business interests to Europe, turning his focus entirely to sponsorship acquisition and driver management.
In the late 1980s and early 1990s he managed drivers competing in Formula 3 and International Formula 3000, developing the network and expertise that would define his later career in Formula One.
In 1994, Zanarini began what would become a nine-year association with Eddie Irvine. He consolidated his full-time management role in 1996 and supported the Northern Irish driver through his years at Ferrari, including the 1999 Formula One season in which Irvine came within one point of the World Drivers' Championship. He continued to represent Irvine during his subsequent stint with Jaguar Racing before the partnership ended in 2002.
In 2003, Zanarini signed Giancarlo Fisichella, shepherding him during successful seasons with Renault F1 — during which the team won back-to-back Constructors' and Drivers' Championships in 2005 and 2006 — and later arranging Fisichella's high-profile move to Ferrari in 2009, replacing Luca Badoer mid-season. This deal was regarded as one of the more complex mid-season negotiations in recent Formula One history, given the circumstances surrounding Felipe Massa's injury.
During this period Zanarini also co-founded Fisichella Motor Sport (FMS) with Fisichella, expanding into team management and the development of young driving talent outside the immediate Formula One grid.
At the end of 2011, Zanarini added Vitantonio Liuzzi — who had competed in Formula One with Red Bull, Toro Rosso, Force India, and HRT across six seasons — to his management portfolio.
In 2013, he signed Antonio Fuoco, then a member of the Ferrari Driver Academy, and in 2015 he signed Antonio Giovinazzi, another Ferrari-associated prospect who would go on to race in Formula One. The signings reinforced Zanarini's established ties to the Ferrari ecosystem and his reputation for identifying and nurturing Italian talent within it.
Zanarini's career spanned the transition from the sponsor-driven 1990s to the driver-academy era of the 2010s. By consistently working within the Ferrari sphere — representing drivers who tested for, raced for, or were developed by the Scuderia — he became a recognised conduit between Italian racing talent and the top level of the sport. His involvement in the founding of Fisichella Motor Sport also extended his influence into team-side operations, bridging the divide between pure representation and motorsport infrastructure.