Jeremy McWilliams entered competitive racing at a relatively late age, beginning at 24 and making his Grand Prix debut at 29 in Australia in 1993 aboard a 500cc machine. He switched between 250cc and 500cc for the next 8 years, joining the Proton KR MotoGP team in 2002 for two seasons. He rode with Aprilia in 2004 but upon their withdrawal in 2005 was left without a ride. After one appearance with the Proton KR team in 2005, he signed with the Ilmor team for the 2007 season, but and after missing most of preseason having suffered a heavy crash that resulted in the loss of two fingers and a broken femur in team testing at the end of 2006, he missed the opening round of the season in Qatar which was to be the one and only run for the Ilmor team.