The son of experienced sports car team owner, restorer and team manager, Kevin Jeannette - Gunnar first drove a race car at aged 15 at a test session at Morosso Park in Florida. Gunnar made his racing debut in 1999 in historic sportscar racing at Road Atlanta. Jeannette competed at the Rolex 24 at Daytona, Sebring 12 Hour and 24 Hours of Le Mans in 2000 - at 18 he was the youngest ever to finish the French classic. He finished second in GT at Le Mans in 2001 and became a factory test driver for Panoz the following year - competing at Sebring, Le Mans and Petit Le Mans with the team. He drove for JML Team Panoz on a full-time basis in 2003, starring at Le Mans to finish fifth overall and third in LMP1 with a brilliant final stint in the car. In 2004, Gunnar drove the new Panoz Esperante GT car in ALMS competition as well as contesting several Rolex Sports Car Series events. He joined Multimatic Motorsports full-time in 2005 contesting the Grand
Am Cup Championship aboard a Ford Mustang FR500C - winning at both at
Fontana and Mosport.