One of the highlights of Maxwell's career came in 2000 at the 24 Hours of Le Mans when he won the LMP 675 class[1] for Multimatic Motorsports aboard a Nissan-powered Lola with fellow Canadians John Graham and Greg Wilkins.

2003 was to also see Maxwell make his NASCAR Winston Cup Series debut, but he failed to qualify the #43 car for Petty Enterprises at Watkins Glen International.

The Canadian co-drove with Grand Am Cup Champion David Empringham in 2005 aboard a Multimatic Motorsports entered factory Ford Mustang FR500C.

In 2006, Maxwell clinched another milestone victory for Multimatic Motorsports when he teamed with David Brabham and Sébastien Bourdais to win the GT2 class at the 2006 12 Hours of Sebring.

[3] In 2008 he won the Grand American Road Racing KONI Sports Car Challenge driver's championship with partner Joe Foster aboard the Hypersports Mustang FR500C run in cooperation with Multimatic Motorsports.