After winning a number of Formula Ford championships, he entered the Aurora F1 championship. Narrowly missing out on the title in 1979 he moved up to Formula 1 in 1980 with the Shadow team. Attempted and failed to qualify for seven races. He then joined the Mazda sports car team.
David Kennedy, from County Sligo in the Irish north-west, began competing in Irish Formula Ford in 1972, winning the title in 1975.
In 1976 he moved to England racing once again in Formula Ford. He impressed by taking two national British Formula Ford 1600 titles and finishing 2nd in the European championship as well.
He skipped British F3 in 1977 and went straight into the European series, racing against Nelson Piquet and Piercarlo Ghinzani. Driving for the works March team, he was forced by budget constraints to switch to Argo to race their JM/Toyota. A less competitive car, David scored two 2nd places at Kassel-Calden and Jarama, finishing 8th in the title standings with 17 points. He stayed with Argo in 1978, but the new car was even less competitive competitive and although he came 6th in the championship, he only scored 13 points with just two 3rd places, at the Nurburgring and at Donington.
Late that year he raced in the Aurora F1 series. An F1 series in Britain for older machinery. Driving a Wolf WR3 Cosworth for the Theodore team in the final round of the championship at Snetterton, he took the fastest lap and beat Tony Trimmer's McLaren to take the win.
A full season of the Aurora series followed in 1979 driving the Theodore run Wolf WR4 run by Theodore. In a good season with two wins, a second and five thirds, he was just two points behind the overall winner, Rupert Keegan. At the end of the year when they took the Wolf to race in the Rothmans Series in Australia, taking a win at Surfers Paradise.
In 1979 Teddy Yip, the owner of Theodore, had sponsored the Ensign team, and in 1980 he help Kennedy land a drive with the Shadow F1 team. Unfortunately the DN11 chassis was just not up to the job. In Argentina for the first round of the World Championship, neither Kennedy nor his team-mate Stefan Johansson were able to qualify. Although David was 1.32 seconds quicker than the Swede, he was still 6.08 seconds off pole. 9.12 seconds of pole in Brasil saw another DNQ. For South Africa, Kennedy was joined Geoff Lees, who qualified 24th however David was 0.77s slower and missed out again. At Long Beach for the USA West GP, Kennedy was almost 2 seconds quicker than Lees and was only 3.829s off pole. But once again it was only good enough for 25th and another DNQ. Both cars also failed to qualify for Belgium and Monaco.
Spain saw the arrival of the DN12 and both Lees and Kennedy qualified in 20th and 22nd positions respectively. Sadly Kennedy's first World Championship Grand Prix only lasted two laps as he was put him out by an accident. The race was later stripped of its championship status.
After failing to qualify again for the French GP, Shadow closed down and was sold to Yip.
In 1981 without an F1 drive, David tried his hand at touring car racing and also raced twice for Richard Cleare in his Porsche 934 at Nurburgring and Brands Hatch. He also contested two Can-Am rounds in America driving the US Racing Frisbee Chevrolet at Watkins Glen and Elkhart Lake.
He only raced once in 1982 driving for the works Chevron team in the Brands Hatch round of the World Endurance Championship. Driving a Chevron B36B Ford with Gerry Amato and Martin Birrane they finished 20th.
He raced in the British Thundersports series in 1983 driving a Ford C100 and also made his debut at Le Mans in the 24 hour classic, sharing his Peer Racing Ford C100 with François Migault and Birrane. They retired after just 16 laps with fuel problems.
Kennedy finally got a break when he was hired by Mazda as their number two driver. At Le Mans he came 15th overall and 4th in C2 with his Mazda 727C shared with Jean-Philippe Martin and Philippe Martin. He raced the car again at Fuji with Yojiro Terada.
In 1984 he had a couple of starts in Thundersports driving an Ibec 300LM Ford.
For 1985 Kennedy became the team's number one driver. Mazda introduced the 737C for both the WEC and the JSPC and David shared his 737C with Terada in the WEC at Silverstone and Fuji.
Takashi Yorino joined the team in 1986 to drive the new Mazda 757 with David. While David also raced in touring cars.
In 1987 Kennedy came 7th at Le Mans with Galvin and Dieudonne in the 757, and 7th at Fuji with Yorino, taking the C2 win in both races.
For 1988 Mazda produced the 767and David continued with his driving and testing roles. A revised 767B was introduced for 1989 but stil without any real success. By 1990 Kennedy was not only Mazda's senior driver but he was also co-ordinating the manufacturer's sports car program. The new 787 was disappointing and unreliable. At Le Mans the Kennedy, Dieudonne and Johansson retired on lap 148 with an oil leak and the sister car of Bertrand Gachot, Johnny Herbert and Volker Weidler retired one lap later with an electrical failure.
Finally in 1991, the 787 and the 787B started to show some reliability and speed. At Le Mans he came 6th while Gachot, Weidler and Herbert took the win, the only one for either a rotary-engined or Japanese car.
Kennedy virtually retired after that though he drove in the 1994 BPR Global GT series in a Chamberlain Engineering Lotus Esprit 300 with Thorkild Thyrring and Andreas Fuchs. Returned to F1 in 2003 as manager of Ralph Firman.
He still races occasionally in historic races and writes and commentates about motor sport for the Irish media.