He won one of the two 1976British Formula 3 Championships and the 1978Formula Two championship. He participated in 82 Formula One Grands Prix, competing for the first time on 11 September 1977. He achieved 1 podium, and scored a total of 14 championship points.
After his sole F1 race in 1977, Giacomelli entered five races in 1978 for McLaren, when his Formula Two commitments allowed. He achieved his best finish, of seventh place, in the 1978 British Grand Prix. After winning the European F2 title, he switched to Alfa Romeo for their return to building F1 cars in 1979. Alfa only entered their 177 and 179 cars in a handful of events that year, and Giacomelli could only achieve a best of 17th place in the 1979 French Grand Prix.
However, the following year the team looked more promising. Giacomelli earned a surprise 6th place qualifying position for Alfa Romeo at Brands Hatch for the 1980 British Grand Prix.[5] Giacomelli posted a third-place qualifying time for the 1980 Italian Grand Prix at Imola. Three of his six mechanics sustained injuries on the Friday before the race, when their helicopter crashed en route to the track.[6] He won the pole position for the 1980 United States Grand Prix at Watkins Glen, New York in his Alfa Romeo. Giacomelli improved on his opening day time by 1.25 seconds, with a time of 1 minute 33.29 seconds over the 3.37 mile track.[7] However, despite these flashes of speed Giacomelli only managed to finish three of the season's fourteen races due to crashes or mechanical breakdowns; although two of his finishes were fifth places at the season-opening 1980 Argentine Grand Prix and the 1980 German Grand Prix, thus netting him four points and placing him 16th in the Drivers' Championship.
In 1981, the car was somewhat more reliable, with Giacomelli being a classified finisher in eight of the season's 15 races - however he struggled to achieve good results until the end of the year, with a fourth and a third in the season-ending Canadian and Caesars Palace Grands Prix respectively - the latter was Giacomelli's only podium finish in F1, and he achieved his best-ever championship finish by ending up 15th in the drivers' standings.
Giacomelli was the test driver for the Leyton House March team in 1988 and 1989, as well as in 1990 in its Leyton House incarnation. He was offered a test driver position with McLaren for 1990 but turned it down.
In 1990, Giacomelli returned to F1 with the Life outfit, taking over from Gary Brabham (who left the team two races into the season). The car, saddled with an ineffectual and fragile W12 engine, struggled to get within 20 seconds of the pole time at many circuits and Giacomelli failed to even get out of pre-qualifying at any of the 12 Grands Prix he contested with the team. At the Portuguese Grand Prix the team reverted to a more conventional Judd V8 engine, but the car had not been adapted for the new engine and the team were unable to properly fit the engine cover,[9] leading to them pulling out of the event without completing a single lap. When Giacomelli was able to drive the Judd-powered car in Spain he found himself 18 seconds off the pace despite the new engine. With money in short supply and few hopes of improving their desperately noncompetitive package the team folded before the final two races of the season, ending Giacomelli's F1 career.
CART
He made 11 starts in CART in 1984 and 1985, 10 of which were for Patrick Racing. His best finish was a 5th place on the Meadowlands street course in 1985. He attempted but failed to qualify for the 1984 Indianapolis 500.
Italian
