John Young Stewart was born on June 11th, 1939, at Rockview, Dumbuck.

His father Bob had been a TT rider and now ran the garage he had built at Dumbuck, R.P.Stewart & Sons, as it came to be known when elder brother Jimmy and then Jackie came into the business, were dealers initially for Austin, then Jaguar.

Jimmy, 8 years his senior, was the first to go into competitive car racing, progressing from Rest-and-be-Thankful hill climbs in his MG and his Healey Silverstone, to driving for Ecurie Ecosse and then Jaguar. He crashed in his Aston Martin DB 3S at Le Mans in 1954 fracturing an elbow, but returned next year as second driver to Mike Hawthorn with Jaguar, but then crashed again on the Nürburgring, damaging the same arm.

His mother, though she loved cars and ran an Austin Atlantic, then a 2½-litre Riley and a Jaguar XK120, persuaded the elder brother to retire, and tried to dissuade her younger son from emulating his brother.

Jackie therefore turned to the outdoors for his recreation. Brother Jimmy being friendly with Alastair Kerr of Inverbeg, Jackie befriended Sir Ivor Colquhoun's head ghillie Duncan McBeth, and they spent five summers stalking together.

He also turned to clay-pigeon shooting, shooting for Scotland, and winning all the home countries' championships in 1959 and 1960, but in the latter year, on his 21st birthday, failed dismally to qualify for the Olympic team.

However his work in his father's garage brought him into contact with Barry Filer, owner of a Porsche Super 90 and an AC Bristol. Jackie began driving Filer's Marcos, Aston Martins and Aces as "A.N.Other". A private test session at Oulton Park in 1962 convinced him he was good enough for professional racing, and his name was eventually passed on by the Goodwood track manager to Ken Tyrell who raced Coopers. At this time he married Helen McNeil of Helensburgh, and the couple moved to a flat in Rhu and then a bungalow at Dumbuck.

Tyrell asked Jimmy how serious his younger brother was, and invited him down to drive against works driver Bruce McLaren. Jackie matched McLaren's time, then beat it. He was signed.

In 1964 he won Formula 3, 2 and 1 races in BRNs plus Lotuses and the Grand Prix teams fell over one another to sign him.

For the next three years he drove for BRM with Graham Hill, finishing 3rd, 7th and 9th in the World Championships. When BRM went into decline Tyrell developed Mantras powered by Cosworth-Ford V8 engines and Jackie took 2nd place in 1968 and next year won his first world championship with 6 outright wins. In 1970 Tyrell switched to a March chassis, but a spate of engine failures reduced Jackie to 5th overall.

In 1971 Tyrell used his own chassis, and Jackie beat the 12-cylinder Ferraris out of sight to gain another 6 outright victories and the world championship. 1972 saw him suffer from a stomach ulcer and indifferent form and he ended up 2nd to Emmerson Fittipaldi.

He entered the 1973 season with the intention of retiring as champion, and beat Emmerson Fittipaldi and Ronald Peterson in Lotuses to win by 16 points with a record 77 points, setting a world championship record of 27 Grand Prix wins, only beaten in 1988 by Alain Proust, and Michael Schuhmacher who retired in 2008 with 91 Formula One victories.

A personal mission of Jackie's was safety in driving. In the year of his successful test session at Oulton Park his friend Bob McIntyre, the TT racer, was killed. In 1968 Jim Clark was killed at Hockenheim, and 2 years later Bruce McLaren died. That same year his friend Piers Courage and Jochen Rindt both died in GP accidents, as did his team-mate Francois Cevert at the end of 1973.

Jackie had his own fright in the Belgium Grand Prix in 1966, aquaplaning during a freak cloudburst and spinning off, breaking a shoulder, cracking ribs and suffering fuel burns. Considered at the time unconventional, i.e. probably non-macho, for his crusade, his views have won through and Grand Prix tragedies are far fewer, with cars now four times safer than ordinary saloons.

In 1985 he said in an interview with Road and Car: "I have never been asked back to give away prizes at my old school. I am little remembered at that school, I think, except for the fact that I was just dumb and stupid". Someone in Dumbarton Academy must have read that article for the next year the boy who had suffered at school from his dyslexia was invited back for the annual prize giving.

All the while Jackie had kept his father's garage going, at a considerable personal cost, but eventually sold it to an old pal of his youth, John Lindsay.

Jackie bought a house on the shores of Lake Geneva where he settled with his family. In 1997 he formed his own F1 team, with his son as team manager, and they came second at Monaco in 1998, won one European Grand Prix race at Nürburgring, had three 3rd places and a pole position in France in 1999.