Button was born on 19 January 1980 in Frome, Somerset. He began karting in 1988 at the age of eight, winning all 34 races of the 1991 British Cadet Kart Championship. He took the European Super A Championship in 1997, becoming the youngest driver and first Briton to win the title. In 1998, Button moved into car racing in the British Formula Ford Championship, winning the title with Haywood Racing and nine victories, and also won the season-ending Formula Ford Festival at Brands Hatch. He finished runner-up in the European Formula Ford Championship the same year.
Having declined to move directly into Formula Three in 1998 on the grounds that he lacked single-seater car racing experience, Button entered the British Formula Three International Series in 1999 with Promatecme, driving a Renault-Dallara F399 car. The Renault engine package was regarded as slightly underpowered compared to the Mugen-Honda units available to rival teams.
Despite the equipment disadvantage and competing against more experienced drivers, Button claimed three race victories over the course of the season — at Thruxton, Pembrey, and Silverstone. He finished the year as the top rookie driver and third overall in the championship, a result that drew substantial attention given that he was in his first season of Formula Three competition. He also finished fifth in the prestigious Marlboro Masters at Zandvoort and took second place in the Macau Grand Prix, losing out to Darren Manning by just 0.035 seconds.
At the end of the season, Button won the Autosport BRDC Award, which included a test in a McLaren MP4/14 Formula One car.
Button chose not to pursue a second Formula Three season. He and his management team declined offers from Ron Dennis to join McLaren and a seat from Jaguar chairman Jackie Stewart. A vacancy at Williams arose following the departure of two-time CART champion Alessandro Zanardi. Button beat Formula 3000 racer Bruno Junqueira in a shoot-out test at Jerez driving a Williams FW21B fitted with a BMW engine, and was signed to race for Williams in 2000.
His Formula One debut season saw him score twelve points in eight place in the Drivers' Championship. A sixth-place finish at the second race of the season in Brazil made him the youngest driver in history at the time to score a World Championship point. Williams had always intended the seat as a stopgap until they could exercise their option on Juan Pablo Montoya, and Button subsequently moved to Benetton on a two-year loan arrangement.
Button's 1999 Formula Three season was notable for the speed with which a driver in his first year in the category — with underpowered equipment and no prior Formula Three experience — reached the top three in the championship. His three victories and top rookie honours generated sufficient momentum to secure a Formula One debut at the age of twenty, bypassing the more conventional Formula 3000 route that most contemporary drivers followed. Button went on to win fifteen Formula One Grands Prix and the 2009 World Drivers' Championship with Brawn GP, a career trajectory that made his brief but effective Formula Three campaign a widely cited example of rapid development through the junior ladder.