At age seven, he came first in the eight- to twelve-year-old karting championship held in Bethany, Connecticut. In 1988, aged eighteen, Nadeau won his first World Karting Association (WKA) Gold Cup championship. Motorsports Talent Scout, Dicken Wear, had seen Jerry Race for a number of years in Karting and asked if he would like to drive his SCCA SS/C Toyota Celica at an EMRA open track event at Lime Rock Park. Jerry caught the eye of Skip Barber and a few other driving instructors that day. Afterward, he was introduced to Bruce MacInnes and fellow graduates Walter Bladstrom, Tom Cotter, Bill Fisher, Bob Kullas, Frank Martinelli, and Art Regan who gave Nadeau financial support. He defended his karting title for the next two years. In 1991, he took the WKA Grand National Championship. In the same year, Nadeau moved into car racing, driving in the Skip Barber Eastern Series. He took eight victories and became the Rookie of the Year. At the end of 1991, Nadeau won the $100,000 Barber Pro Series shoot-out, allowing him to race in the Barber Dodge Pro Series.