Gunnar Axel Arvid Nilsson was born on 20 November 1948 in Helsingborg, Sweden. He followed an unconventional path into motorsport, first completing engineering studies at Stockholm University and serving as a submarine radio officer in the Swedish Navy before starting his racing career in the late 1960s. He built a successful transport business alongside his early racing activities, demonstrating the organisational ability he would later bring to his charitable work.
His junior career peaked with victory in the 1975 British Formula 3 Championship, driving for March. This performance earned him a seat at Team Lotus for 1976, where he joined Mario Andretti as the team developed the new ground-effect Lotus 77 and then the Lotus 78.
Nilsson made his Formula One debut at the 1976 South African Grand Prix and qualified for every race in his rookie season. His performances included third place in Spain and Austria. He retained his Lotus seat for 1977, and at the rain-soaked Belgian Grand Prix at Zolder he produced one of the season's most memorable drives. Running in difficult changing conditions and suffering from a vibrating wheel nut that forced a tyre stop, Nilsson pushed hard on fresh rubber and passed Niki Lauda's Ferrari from the outside with twenty laps remaining to take the lead. He held on to win, claiming his first and only Formula One victory. Further points followed at Dijon and Silverstone.
Toward the end of 1977, his performance declined and he experienced a string of retirements. By that stage he was already experiencing early symptoms of illness. He signed with the Arrows team for their debut 1978 season but was unable to race before his health deteriorated further.
In December 1977, a routine check-up in London confirmed that Nilsson had testicular cancer. He underwent intensive radiotherapy at Charing Cross Hospital, but the disease spread to his lymph nodes and his decline was rapid. By July 1978 he had lost over 30 kilograms and all his hair, but continued to speak of a possible return to racing.
Having resigned from Arrows, Nilsson chose to spend his remaining time establishing the Gunnar Nilsson Cancer Foundation, affiliated with Charing Cross Hospital. He declined pain-killing medication in order to remain functional for as long as possible and focus on the foundation's work. George Harrison contributed to the fund through a charity single released in the UK, featuring tracks from his 1979 album.
Nilsson died on 20 October 1978, five weeks after the death of fellow Swede Ronnie Peterson, who had been his rival and friend. Peterson's death from crash injuries at Monza had deeply affected Nilsson in his final weeks. He was 29 years old.
The Gunnar Nilsson Memorial Trophy was held in 1979, won by Alan Jones. Nilsson is remembered in Formula One as a driver whose talent had been recognised as exceptional by contemporaries including Mario Andretti, who called him his first true friend among racing drivers. His obituary in The Times described him as "perhaps the most naturally gifted of the new generation of grands prix drivers."
The Gunnar Nilsson Cancer Foundation represented an unusual act for a racing driver of the era: using public profile not to market a comeback but to build a lasting institution in the face of terminal illness. Nilsson's combination of engineering intellect, competitive drive, and personal warmth, described by those who knew him as both charismatic and privately complex, made him one of the more distinctive figures of the 1970s Formula One generation.