Robert Dunlop made his road racing debut at the Temple 100 in 1979 as a teenager, after an apprenticeship on short circuits. His first Cookstown 100 appearance followed in 1980 on a 347cc Yamaha, and his first professional sponsored race came at Aghadowey in 1981. He began accumulating wins at the Cookstown 100 from 1985 onward, eventually recording eight victories at the event. His most successful single year there was 1987, when he swept the 125cc, 350cc, and 1000cc races to earn the "Man of the Meeting" honour.
Dunlop won the 1983 Newcomers 350cc Manx Grand Prix on his first appearance at the Isle of Man, beating future TT winners Steve Hislop and Ian Lougher. His full TT career produced a string of wins and podiums across more than a decade of competition.
He took his first TT win in 1989 in the 125cc class with a new lap record of 165.79 km/h, and repeated the win in 1990 and 1991, setting further records each time. In 1991 he added the Junior TT. Over his career he finished on a TT podium 14 times — a record of consistency that reflected the same technical precision he applied across all road circuits.
The North West 200, held on public roads near Portstewart and Portrush, was a particular stronghold for Robert. He and his brother Joey between them held a record number of wins at the event. Robert's 15th win at the North West 200 meeting in 2006 was itself a record-breaking achievement, cementing a legacy at the circuit that spanned more than two decades.
At the Macau Grand Prix in 1989, riding a Honda 500, he defeated Phillip McCallen and Steve Hislop — both on Honda 750s — to take the overall victory, a performance notable for the displacement disadvantage he overcame. He also competed in the 1990 season with the JPS Norton team on the Rotary-engined RCW588, winning one of three MCN Supercup rounds alongside other notable short-circuit results.
In the 1994 Isle of Man Formula One TT, the rear wheel of Dunlop's 750cc Honda RC45 collapsed in a long left-hand turn just after the jump at Ballaugh Bridge. The crash caused multiple severe injuries, including tendon damage and a shortened leg. His recovery kept him out of competition for the remainder of 1994 and all of 1995, and many believed his career was finished.
Dunlop returned at the Cookstown 100 in April 1996, still not fully fit, and took ninth place in the 125cc race. In 1998 he won the Ultra-Lightweight TT, demonstrating that his recovery had been real. He continued to compete in the 125cc class at road racing events, accepting the limits imposed by his injuries rather than attempting a return to the full-capacity classes he had previously dominated.
In December 2003 he announced his intention to retire after the 2004 season. He subsequently returned to competition in 2005 and 2006, motivated in part by the desire to win further races and to pass his experience to his sons William and Michael, who were beginning their own careers.
On 15 May 2008, during a qualifying session at the North West 200, the engine on Dunlop's 250cc motorcycle seized. He instinctively applied the front brake, which on his specially modified machine was located beside the clutch rather than in the standard position, and was thrown over the handlebars at approximately 155 mph. A following rider, Darren Burns, collided with him and sustained a broken leg and concussion. Dunlop was taken to Causeway Hospital in Coleraine, where he died shortly after 22:00. His son Michael won the race later in the meeting and dedicated the victory to his father. Robert Dunlop was buried at Garryduff Presbyterian Church in Ballymoney beside his brother Joey.
Robert Dunlop was elected as the first inductee into the Irish Motorcycle Hall of Fame in February 2005. In 2006 he and Joey were awarded honorary Doctorates of the University from the University of Ulster in Coleraine. The Robert Dunlop Memorial Garden in Ballymoney, established in 2010, adjoins the earlier Joey Dunlop Memorial Garden. In 2022 a statue of William Dunlop — Robert's son who died in 2018 — was added to the site, making it a memorial to three generations of a racing family.
The Dunlop family's contribution to road racing has no parallel in the sport's history: Joey with 26 TT wins, Robert with multiple TT victories and a record-breaking North West 200 career, and the next generation in Michael and William continuing the lineage. Robert Dunlop's career, defined by both achievement and resilience in the face of injury, holds its own place within that story.