LaJoie made his NASCAR Winston Cup debut in 1985 at Atlanta Motor Speedway. Driving the No. 07 Snellman Construction
Chevrolet owned by Bob Johnson, he started sixteenth and finished 14th. He ran his next race the following season at
Pocono Raceway, where he finished 29th after suffering engine failure. He also made his Busch Series debut that season, running four races in his own No. 03
Pontiac, posting a 10th-place finish at
Charlotte Motor Speedway. He ran another race in 1987 at
Dover International Speedway and finished tenth. After a third-place finish the following season, he joined
Frank Cicci Racing mid-way through 1989 and had a career-best second-place run at
Hickory Motor Speedway. He ended the season 26th in points. LaJoie did not return to Cicci in 1990, and ran a handful of Busch Races in his own No. 71, his best finish was 23rd at
Richmond. He did not run another NASCAR-sanctioned race until 1993, when he got selected to run the No. 20 Fina car owned by
Dick Moroso at Talladega. This would turn out to be a shrewd career move for LaJoie as he ran up front with the leaders all afternoon and finished a surprising second. This got LaJoie five more races for Moroso and one for
BACE Motorsports in the Busch Series. His best finish was second, twice. In 1994, he was a thought by some to be a dark horse for the championship. He drove for Moroso full-time in the No. 20 Fina Lube Chevy that season posting seven top-tens. LaJoie led the point standings early in the season before a string of poor results, also a lack of performance dropped him to 16th in the final point standings. He also ran three Cup races, finishing in the top-20 in all three of them that season. ==1995–2002==