The heir to the Bonniers Aktiebolag publishing empire, Bonnier was an international socialite, making his home in Switzerland long before it became the vogue. He started in Formula 1 in 1957 with a Maserati and his greatest claim to fame was to win BRM's maiden Grand Prix victory at Zandvoort in 1959. He was highly competitive in the early 1960s and won the German GP (a Formula 2 race) in 1960. That same year he won the Targa Florio in a Porsche partnered by Hans Herrmann and Graham Hill. He then won the Sebring 12 Hours in 1962 and the Targa Florio for a second time in 1963. He continued to race in F1 in private entries long after he was competitive, although he was one of the driving forces behind the Grand Prix Drivers' Association.