Greg entered the Craftsman Truck Series in 1997, with the same vigor he showed in late models by establishing a rookie record for Bud Pole Awards in the series with four, and leading at least one lap in 12 different events on his way eight top-five and 12 top-10 finishes and the rookie of the year award. Greg furthered his winning ways by capturing the 2000 Truck championship.
Greg moved again, this time to the Busch Series in which he had arguably the best rookie season in Busch Series history. In his 33 race starts he won five times with two Bud Poles, 16 top-five and 21 top-10 finishes. He was a phenomenal qualifier, with 25 top-10 starting spots and an average starting position of 8.6 on his way to the rookie of the year award.
Despite winning "just" four times in 2002 Busch Series campaign, Greg averaged a top-10 finish and garnered 20 top-five finishes in 34 starts. As a result, he became the first driver to win both the Truck and Busch titles. He was also the first Roush Racing driver to win a major NASCAR title of any kind.
Because of his past performance, Greg was given an opportunity to run the Cup Series in 2003 and wasted little time visiting Victory Lane by taking the checkered flag in the Pepsi 400 at Daytona. In all, Greg garnered three top-five and six top-10 finishes, coming up second in the rookie of the year race.
