Crafton was born in Tulare, California. He began racing go-karts at age seven and won multiple national and regional karting championships before moving to midgets at fifteen, winning twenty main events. He joined the Featherlite Southwest Series as a substitute for his injured father Danny Crafton in 1996 and took over the No. 46 entry full-time in 1997. Crafton won the Featherlite Southwest Series championship in 2000 on the strength of four wins.
Crafton made his Truck Series debut at the 2000 season finale at California Speedway for ThorSport Racing, qualifying seventeenth and finishing ninth. He drove the No. 88 full-time from 2001 onward, with Menards joining as an associate sponsor in 2002. His early years were defined by consistent top-ten finishes without wins; in eleven top-tens in 2001 he finished twelfth in the championship.
In 2004, Crafton drove the No. 6 for Kevin Harvick Incorporated, posting six top-fives and seventeen top-tens to finish fifth in the championship. Despite strong results, he was released and returned to ThorSport for 2005. His long wait for a first win ended at Charlotte Motor Speedway on May 16, 2008, in his 178th start — the record at the time for most starts before a first Truck Series win. In 2009, without a win, Crafton scored 11 top-fives and 21 top-tens to finish second in points behind champion Ron Hornaday.
Crafton's championship run began in 2013. He won at Kansas in April, led the points for the remainder of the season, and completed every lap of the year — the first driver to do so in the Truck Series — to claim his first title. In 2014 he won at Martinsville and Texas and became the first back-to-back champion in Truck Series history. The 2015 season was his most prolific by wins (six), with victories at Atlanta, Kansas, Texas, Kentucky, Martinsville, and Homestead. Despite those results, Erik Jones took the championship and Crafton finished third in points.
After a winless 2018 and 2019, Crafton nevertheless made the Championship 4 in 2019. He finished second at Homestead, ahead of Ross Chastain, to claim his third Truck Series title — becoming the first driver to win a NASCAR series championship without winning a race that season.
Crafton broke a 67-race winless streak by winning at Kansas in July 2020. He made the Championship 4 again in 2021 but finished fourth in the title race. He failed to qualify for the playoffs for the first time in 2024. In August 2025, it was announced that Crafton would retire from full-time competition at the end of the 2025 season, with teammate Ty Majeski taking the No. 88 seat in 2026. Crafton confirmed plans to return for five to ten races per year on a part-time basis.
Crafton holds the all-time record for most Truck Series starts and the record for most consecutive Truck Series starts (592). In the third race of the 2013 season, he surpassed Terry Cook's previous record of 296 consecutive starts. He was the first driver to win back-to-back Truck Series championships, and the first to claim a series championship without winning a race in that season.
Crafton competed in the NASCAR Cup Series on a handful of occasions, including driving the No. 18 Joe Gibbs Racing Toyota in the 2015 Daytona 500 as a substitute for the injured Kyle Busch, finishing eighteenth. He also competed in the Michelin Pilot Challenge at Sebring in 2019 alongside ThorSport teammates Grant Enfinger, Ben Rhodes, and Myatt Snider.
Crafton's twenty-five full-time seasons at ThorSport Racing, conducted largely with the same truck number and the same sponsor (Menards), represent one of the most stable and enduring partnerships in NASCAR's lower series. His three championships, consecutive starts record, and longevity define a career built on consistency over a quarter-century in the Truck Series.