1998–2001 In 1998, Hamilton began to run some
Busch Series races for the Sadler Brothers Racing No. 95 team. He made his debut at
Rockingham in October, where he started in 27th position. He led four laps and finished 37th, three laps off the lead. He also made the race at
Atlanta, had a nineteenth place start and twentieth-place finish. Hamilton and the No. 95
Shoney's Inn team entered 1999 with a part-time schedule. In four races with the team, his best start was sixth at Daytona, and his best finishes were 27th at Rockingham and
Darlington. Hamilton did not race again until the
Hensley Motorsports No. 63
Exxon Superflo team had an opening. He ran six of the next seven races, beginning at Watkins Glen. In that seat, he set his best career finish of 21st at
Pikes Peak. Hamilton then moved over to the No. 22
Air Jamaica Team owned by Carroll Racing. He qualified for all the races he attempted, and matched his career best start of sixth at
Charlotte. At
Homestead-Miami Hamilton started fifteenth and finished ninth. Hamilton got a full-time ride with Carroll in 2000, driving the newly formed No. 26 Chevy, with sponsorship from
Baywatch. Hamilton had three top 10s in 2000, with a fourth at Talladega, and a pair of sevenths at Charlotte and
Memphis. Hamilton also won his first career pole in the season finale at Homestead-Miami. He finished 19th in points. During the Homestead weekend in 2000, he made his Winston Cup Series debut at that track, driving the No. 57 Chevrolet owned by his father. He finished 33rd in that race, six laps down. He drove the No. 01
Coors Light Chevrolet for
SABCO Racing the following week to a 31st-place finish. Hamilton returned to Carroll had a pair of fifth at Darlington and Rockingham in 2001. He also added three other top-tens and won another pole at
Fontana in addition to starting in the top-ten for half the races. After finishing seventeenth in points, he left the team. He made his Truck Series debut that year at
The Milwaukee Mile in the No. 4
Dana Dodge Ram for
BHR but exited early due to a
transmission failure. He also ran three races in the No. 33
Oakwood Homes Chevy for
Andy Petree Racing as a teammate to his father, filling in for the injured
Joe Nemechek. He also ran seven Cup races late in the season for
Morgan-McClure Motorsports, driving the No. 4
Kodak Chevy to three top-twenty finishes.
2002–2006 in August 2007 In 2002, Hamilton joined
Team Rensi Motorsports to drive the No. 25
United States Marine Corps-sponsored
Ford Taurus. He won his first career race at New Hampshire and finished eighth in points. He also had his first top-five finish in the Truck Series at
Nashville Superspeedway, finishing seventh in his father's
Square D entry. He had his statistically career-best season in 2003, where he won four Busch Series races and finished fourth in the final standings. He also partnered with Rensi to run some races at the Winston Cup level, his best finish being a fourteenth at
Kansas Speedway in the No. 35 Marines Ford. Hamilton returned to Rensi in
2004, but did not win a race. He competed in six Nextel Cup events for
Phoenix Racing in the No. 09
Miccosukee Indian Gambling-sponsored Dodge and had a best finish of seventeenth. He also drove three times in the Truck Series, winning a pole in his father's No. 04 truck, as well as running twice for
HT Motorsports. After 23 Busch races, he left Rensi to move up to the Nextel level, driving the No. 32
Tide-sponsored Chevrolet for
PPI Motorsports. He was given the full-time ride for
2005, but struggled immensely, failing to qualify three times and not finishing any higher than eleventh. After driving two events in equipment leased from
Front Row Motorsports, Hamilton was let go from PPI at the end of the season. Without a full-time ride, Hamilton moved to the Truck Series, leasing equipment from the No. 08 team owned by
Green Light Racing and running with Corky's Ribs and BBQ sponsorship. After three races, it was announced that his father had been diagnosed with
head and neck cancer, and Hamilton was deemed his replacement in the No. 18 Fastenal-sponsored Dodge. He won the pole in his first race in the truck but only mustered a sixteenth place finish in points, as well as dealing with conflicts within the family-run organization. His attempt to run the
2006 Allstate 400 at the Brickyard at the Cup level also failed. Following his father's death on January 7, 2007, Hamilton was expected to take over ownership of the team; however, he was not part of the management named by the team's backers the following month. The team eventually closed down in 2008.
2007–present In
2007, Hamilton returned to the Busch Series and Team Rensi, this time driving the No. 35
McDonald's Ford. He had three top-ten finishes and finished sixth in the final standings. After his #35 team folded in 2008, he moved back to the No. 25 car with
Smithfield Foods sponsoring for thirty races. Despite missing two road course events, Hamilton had two top-tens and finished fifteenth in points. The team was ready to close near the end of the season when Smithfield's sponsorship ended, but Hamilton funded the team out of his own pocket for the final few races of the season to keep the team going. He also purchased a small portion of the Sadler Brothers team for whom he had begun his career, allowing them to run a limited schedule in the Nationwide and
ARCA RE/MAX Series. Before the 2009 season, Hamilton purchased a small portion of Rensi Motorsports and merged his own operation with the team, forming the new
Rensi-Hamilton Racing operation. The No. 25 team lacked the sponsorship to run Hamilton, and he subsequently drove
Randy MacDonald's #81 Dodge for a limited schedule. Hamilton returned to the Truck Series in 2010 for
Rick Ware and also ran at
Nashville Superspeedway in 2011 with Ware in their No. 1 truck. After two years away from major-league racing, Hamilton returned to the track in 2014, signing with
Carter 2 Motorsports to drive the team's No. 40 Dodge full-time in the
ARCA Racing Series; however before his first race with the team, he was released. In 2015, Hamilton resigned with Carter 2 Motorsports to compete in the 2015 ARCA season. In 2016, Hamilton started Hamilton-Hughes Racing, with none of the three cars entered at Daytona making the field. By the end of May, cars from Hamilton-Hughes Racing were no longer showing up to the track. Most recently Bobby is facing lawsuits from multiple drivers and the team has been evicted from its
Russellville, Kentucky shop. ==Other ventures==