Outside of Formula One, Bonnier entered 13 editions of the 24 Hours of Le Mans from 1957 to 1972, finishing runner-up in 1964 alongside Graham Hill, driving the Ferrari 330P.

He debuted a 1500cc Maserati and moved up through the field following a bad start, passing Luigi Musso, and was gaining on leader Eugenio Castellotti at around two seconds per lap when he lost control after another car pulled directly into his path as they negotiated a fast corner.

His greatest achievement in Formula One was taking victory for BRM in the 1959 Dutch Grand Prix at Zandvoort, when the notoriously unreliable car worked well for once (Dan Gurney and Hans Herrmann had bad crashes after brake failures).

Despite his win for BRM, Bonnier did not drive for many works teams throughout his career, with only one-offs as a replacement driver for Lotus, Brabham and Honda.

While filming the 1966 Belgian Grand Prix at the notorious and extremely fast Spa-Francorchamps circuit, Bonnier, along with more than half the field including Jackie Stewart, Bob Bondurant, Graham Hill and Denny Hulme, crashed out on the first lap of the race.

He won the 1960 Targa Florio, co-driving a works Porsche 718 with Hans Herrmann, and in 1962 took a Ferrari 250 TRI entered by Count Giovanni Volpi to top honours in the 12 Hours of Sebring, sharing the car with Lucien Bianchi.

He then won the 1000km Nürburgring in a Chaparral in 1966 (with Phil Hill), his last win in a major sports car event, but still managed to snatch victories in the minor 1000 km of Barcelona at Montjuïc in 1971 (with Ronnie Peterson), and the 4 Hours of Le Mans in 1972 (with Hughes de Fierlant).

In the first outing at the Karlskoga Sweden GP, Bonnier had the pole but an off course excursion on the first lap caused him to finish second to David Piper in a Ferrari 330P3/4.

On the straight between Mulsanne Corner and Indianapolis, his open-top Lola T280-Cosworth collided with a Ferrari Daytona driven by a Swiss amateur driver Florian Vetsch.

According to Vic Elford, who was driving a factory-entered Alfa Romeo Tipo 33 and who had stopped to assist Vetsch escape from his burning Ferrari, the last he had seen of Bonnier's Lola was that it was "spinning into the trees like a helicopter".