Manning, a native of North Yorkshire, England, began his racing career in karts at age 10 before moving into open-wheel formula cars in England. He recorded numerous victories in Formula Vauxhall and F3, and won the 1999 All Japan F3 Championship on the strength of six victories. Manning served as a test driver for the BAR Honda Formula One team from 2000 through 2002 and made his Champ Car debut driving for Team St. George at Rockingham Motor Speedway in 2002, leading 18 laps and finishing ninth.
From 2004 until mid-2005, Manning was the driver of the No. 10 Target Chip Ganassi Racing entry in the IndyCar Series. In his time of service with Ganassi Racing, he scored four top fives and 13 top 10s.
In 2007, Manning returned to the IndyCar Series as driver of the No. 14 ABC Supply Dallara-Honda for A.J. Foyt Enterprises. He finished 13th in the point standings.