Stoner began competing at age four and won his first race at age nine. At age 14, Stoner and his parents moved to England, where he later won the English 125cc Aprilia Championship in 2000.

In 2008, Stoner was named Young Australian of the Year.

His first race was when he was four years old, in an under nine years old race at the Hatcher's dirt racing track on the Gold Coast of Australia. Between his very first race win at the age of nine and the age of fourteen, young Casey Stoner won 41 dirt and long track titles and 70 state titles. One feat he achieved that illustrates his passion and "need" for racing was done at age twelve. Over one weekend he raced in 5 different categories in all 7 rounds of each capacity. A weekend consisting of 35 different races... Not only did he compete in all these categories and different engine capacities, the young Casey Stoner went on to win 32 out of the 35 races. There were five Australian titles to be won that weekend, Casey Stoner won all 5.

The legal age to enter into road races in Australia is 16. At the age of 14 years, Casey Stoner and his parents agreed he was ready to move up onto road racing so they packed up the family and moved to England - where the legal age for road racing is 14.

From 2000 to 2002, he contested the national 125cc GP championships in Britain and Spain, winning the English 125cc Aprilia Championship in 2000, before moving fulltime to the 250cc GP World Championships in 2002. His season on an Aprilia under the guidance of Lucio Cecchinello was turbulent, with no podium places from 15 race starts.

125cc
In 2003 Stoner moved to the 125cc GP category. Here, working again with Cecchinello and Aprilia, he met with considerable success, scoring his first GP race win and three second places, finishing 8th overall at the season's end.

In 2004 Stoner joined the Red Bull KTM factory team in 125cc class and continued to improve, with another race win, two second places, three thirds, and a final championship position of fifth.

250cc
In 2005 he rejoined the 250cc world championship class, racing once again for Lucio Cecchinello on an Aprilia. Onboard a factory Aprilia, Stoner emerged toward the season's end as a serious threat to championship leader Dani Pedrosa; a threat that only dissipated with a crash at Stoner's home Grand Prix of Phillip Island, allowing Pedrosa to establish an insurmountable points lead. Stoner went on to claim a solid second place in the overall championship standings, with an impressive five race victories for the season.

MotoGP
Stoner was in advanced negotiations with Yamaha, but after they dropped them he settled on an alliance once more with team manager Lucio Cecchinello on a Honda RC211V, on a one-bike team new to the series for the 2006 Season. He took pole for only his second race, but crashed several times. He finished his debut season in 8th position with his best result being a 2nd place at the Turkish GP, where he was overtaken on the final corner by Marco Melandri.

Stoner secured a ride with the factory Ducati team for the 2007 season, joining Loris Capirossi on the new 800cc Ducati Desmosedici GP7. He recently signed a contract extension with Ducati that will see him remain with the team for the 2008 and 2009 seasons (in which he will partner Italian Marco Melandri), with a further option for a 4th season in 2010.