Nadeau arrived in NASCAR, the highest and most expensive level of stock car racing in the United States, with a limited budget.

After Nadeau took his first Top Ten finish at Talladega Superspeedway in 1999, he won his first NASCAR sanctioned race in the Winston West Series at Las Vegas Motor Speedway.

Nadeau achieved his top NASCAR season in 2001 when he finished 17th in points, but his racing career ended in 2003 after he suffered serious injuries in a practice crash.

His parents were Gerald Joseph, a roofer, and veteran in the United States Army during the Vietnam War (1944–2007) and Pauline Cyr Nadeau.

[3] Nadeau was educated at Henry Abbott Technical High School and studied automotive technology.

[6] Speaking about his father's role in his career, Nadeau said, "I learned a lot from my dad, Gerry, while I was growing up.

[7] 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.

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.

[9] In the same year, Nadeau moved into car racing, driving in the Skip Barber Eastern Series.

[8] Nadeau drove alongside sports car driver Gene Felton for the Jill Prewitt team which entered the 1992 12 Hours of Sebring, but retired after forty-eight laps because of a differential problem.

Nadeau later stated the experience helped him to develop the skill of not using his car's brakes on slippery surfaces.

[13] Nadeau moved to North Carolina that year on the advice of public relations worker Tom Cotter,[5] and was on a budget of $200.

In Formula Opel, he drove a partial season, running in thirteen out of seventeen races for six teams and finished sixth overall, the highest for an American driver.

[5] In November 1996, Nadeau and Barber Dodge Pro Series driver Tony Renna represented the United States in the EDFA Nations Cup held at Donington Park and won the silver medal, finishing behind Germany.

Nadeau also built his own cars for Automobile Racing Club of America (ARCA) and Busch Series events.

[19] Nadeau made all five races, including a ninth-place qualification at New Hampshire International Speedway, but failed to finish higher than thirtieth and was let go at the end of his contract when the team's sponsor expressed no interest in retaining him.

[23] Nadeau's performances during the season caught the interest of 1988 Champion Bill Elliott and quarterback Dan Marino, and they offered him the chance to become their second driver.

[28] In that year, Nadeau won his first NASCAR-sanctioned event in the Winston West Series at Las Vegas Motor Speedway.

He nearly clinched victory in the penultimate race of the season at Atlanta, finishing fourth after running out of fuel midway through the final lap.

In early May, Nadeau and Hendrick Motorsports agreed to terminate his contract, citing a lack of performance.

[39] Afterward, Nadeau drove for Petty Enterprises at Sonoma where he came close to winning his second Winston Cup race, having a 5 second lead with 3 laps to go but finishing thirty-sixth after his car suffered a broken rear-end gear on the race's 107th lap.

Nadeau suffered complete immobility of the left side of his body, a skull fracture, concussion, a collapsed lung, and several broken ribs.

[51] In fall 2003, Nadeau began discussions with MB2 Motorsports boss Jay Frye about a long-term comeback.

Frye gave Nadeau a test at Concord Speedway,[52] where he was unable to feel his car's brake pedal.

[54] While Nadeau received a small financial settlement from NASCAR, it was not enough to pay for all of his rehabilitation, so he sold his large house near Lake Norman and moved to Davidson, North Carolina.

[14] MB2 Motorsports entered into a partnership to create a recovery driving program for Nadeau which included competing in the Nextel Cup, the Busch Series and ARCA events in 2004.

[56] During that year, Nadeau served as a karting instructor at Lime Rock Park and returned to NASCAR as a spotter for Busch Series driver Todd Szegedy.

In 2011, Nadeau became a mentor to Truck Series rookie Jeffrey Earnhardt, son of Kerry and grandson of Dale.

In a 2016 interview with Autoweek, Nadeau was candid about his life after the crash:People don't understand how difficult it is living with a head injury.