Sawyer began his Busch Series career in 1983, running a handful of races and scoring eight top-tens while operating his own team across 1983, 1984, and 1985. From 1986 through 1989 he raced full-time for Lewis Motorsports, finishing between fourteenth and eighteenth in the series standings each year while accumulating numerous top-ten finishes. Despite his consistency, Sawyer did not win during his four seasons with Lewis and subsequently moved to the team owned by A. G. Dillard.
His best early-career season came in 1990 with the Dillard organization, where he recorded four top-fives and finished thirteenth in the Busch Series standings. Sponsorship difficulties hampered the team in 1991 and beyond, and Sawyer was limited to just a handful of starts across 1992 and 1993 as he searched for a stable ride.
Sawyer's fortunes improved dramatically in 1994 when he secured a seat at Sutton Racing. He claimed his first Busch Series victory that year at Myrtle Beach Speedway and finished fourteenth in the championship. In 1995 he balanced dual programs — continuing with Sutton in the Busch Series while also replacing Loy Allen Jr. in the No. 27 Winston Cup car for Junior Johnson and Associates. His Busch campaign that year was his strongest to date, finishing ninth in the standings. He also participated in the Winston Select exhibition event, driving Junior Johnson's car.
After a partial 1996 Cup campaign with David Blair Motorsports was cut short by sponsorship issues, Sawyer stepped back to the Busch Series. He rejoined Sutton Racing in 1997, finishing eighth in the standings, then recorded a fifth-place points finish in 1998 with ten top-tens across the season.
In 1999, Sawyer joined Akins Motorsports and had one of his most competitive campaigns. He won at New Hampshire International Speedway, added fourteen top-ten finishes, and finished fifth in the Busch Series standings. The 2000 season was similarly strong, with fourteen top-tens and a sixth-place points result.
The 2001 season proved to be Sawyer's last full-time campaign. He turned in a career-high nineteen top-tens and finished fifth in Busch Series points with Akins Motorsports. The team was sold mid-season and ultimately folded after the year, leaving Sawyer without a ride. He made three more Busch starts in 2002 for Brewco Motorsports, filling in for an injured Jeff Purvis, but could not secure a full-time seat as teams increasingly prioritized younger drivers with personal sponsorship backing.
Sawyer transitioned from driving into NASCAR's administrative structure. He served as director of team operations for Action Express Racing in the TUDOR United SportsCar Championship before returning to NASCAR's central offices. In February 2015, NASCAR announced his appointment as managing director of the Camping World Truck Series, replacing Chad Little.
Sawyer subsequently rose to Vice President of Officiating and Technical Inspection, and later to Senior Vice President of Competition — one of the most senior technical and regulatory roles within the sanctioning body. In that capacity he was a key figure in the development of the Next Gen car, which debuted in the Cup Series in 2022 alongside engineer John Probst. The Next Gen program represented a comprehensive overhaul of the Cup car's architecture, introducing a common chassis, independent rear suspension, and centralized parts sourcing.
Sawyer's career represents a transition from a respected but underfinanced Busch Series competitor into a powerful voice in NASCAR's regulatory and technical governance. His work on the Next Gen car in particular had a lasting effect on the sport's on-track product and competitive balance.