Paul Stewart was born in Scotland but moved to Switzerland before the age of three, growing up near several racing drivers including Jochen Rindt and Jo Bonnier. He learned to drive sitting on his father's knee, steering cars along the family driveway. He attended Aiglon College and later Duke University in North Carolina, where he studied political science. Jackie Stewart had agreed to support his son's motorsport ambitions only after he graduated. Paul worked in financial institutions in New York and Switzerland during holidays and, before graduating, secretly enrolled in a racing course at Brands Hatch under the name Robin Congdon to ensure he received an honest assessment of his ability.
After graduating, Paul revealed his racing ambitions to Jackie, who initially opposed the idea but ultimately decided he would rather be directly involved than have others manage his son's career. The two began collaborating and formed Paul Stewart Racing.
Paul entered Junior Formula Ford 1600 in the summer of 1987, leading races and scoring podiums. The Paul Stewart Racing brand became a fully-fledged team in 1988, fielding a Formula Ford 2000 car with Camel sponsorship, aided by Jackie's former mechanic Roy Topp, ex-Brabham chief mechanic Graham Lewins, and James Skilling. After a win at Cadwell Park, the operation stepped up to British Formula 3 in 1989.
In Formula 3, Paul competed against future Formula One and IndyCar drivers including Mika Häkkinen, David Coulthard, Gil de Ferran, and Kenny Bräck. He won at Snetterton in unusual circumstances: leading the race, he spun avoiding a backmarker at the Russell complex but crossed the line backwards just as the race was red-flagged following an accident involving Häkkinen; he was awarded the victory on countback. The result earned him a grid spot at the Macau Grand Prix, where he qualified third and was named best newcomer.
Stewart competed in Formula 3000 from 1991 to 1993, with teammates including Marco Apicella, Coulthard, and de Ferran. His best individual result was third at the Pau Grand Prix in 1993. Despite testing for the Footwork Formula One team, he concluded that his talents were better suited to management and retired from driving to focus on building Paul Stewart Racing into a serious operation.
Under Paul's leadership, Paul Stewart Racing grew well beyond supporting his own career. The team won 12 titles and 119 races across various categories including Formula Vauxhall Lotus, Formula 3, and Formula 3000. Its success and infrastructure became the foundation on which Stewart Grand Prix was built when Jackie secured the Ford works deal in 1996.
Paul and Jackie co-founded Stewart Grand Prix, which competed in Formula One from 1997 to 1999 as Ford's factory-backed team. Paul served as Chief Operating Officer. The team's 1999 season was its strongest, delivering a victory for Johnny Herbert at the European Grand Prix and fourth place in the constructors' championship. At the end of 1999 Ford purchased the team outright, renaming it Jaguar Racing for 2000.
In September 1999, Stewart was diagnosed with ulcerative colitis. A further diagnosis of bowel cancer followed in April 2000. Upon receiving the news he stepped down as Chief Operating Officer of Jaguar Racing and travelled to the Mayo Clinic in the United States for treatment. A subsequent CAT scan showed no signs of cancer returning.
Paul Stewart is married to Victoria, whom he wed in 1993, and has four sons. His younger brother Mark works as a film producer.