He was a Formula One test and reserve driver in 2004 for the Minardi F1 team, taking part in the Friday practice sessions during Grand Prix weekends, making 17 appearances in all.

Born in Bree, Leinders was one of the most successful Belgian racing drivers of the nineties and the beginning of the 21st century.

In his second year, he won the Championship and was invited by the McLaren Junior team to partner Nick Heidfeld in the last race of the Formula 3000 season.

From 2005, Leinders was a regular racer in the FIA GT Championship with Belgian Racing, driving a Belgian-built Gillet Vertigo.

In 2014, he ran the entire season of the NASCAR Whelen Euro Series with Marc VDS Racing's Toyota Camry in the Elite 1 category.

After Marc VDS's victory in the 2015 24 Hours of Spa, Leinders announced he parted ways with the team.