At the Commonwealth Games 2002 , Devonish won silver over 200 meters and again gold with the English relay, which competed in the line-up of Gardener, Devonish, Allyn Condon and Campbell. A fortnight later he won the bronze medal over 200 meters at the 2002 European Championships in Munich. The British season with the cast Christian Malcolm , Campbell, Devonish and Chambers won the season finale. This medal was subsequently revoked from the relay because Dwain Chambers was retroactively suspended for doping. The lock for Chambers covered the period 2002 and 2003, so that the British relay was stripped of the silver medal at the 2003 World Championships . The season ran with the same line-up as in Munich 2002.
At the beginning of 2003, Devonish had achieved its greatest success without a relay when he won the 200-meter title at the World Indoor Championships in Birmingham . His greatest success with the relay he achieved at the 2004 Olympic Games , when the British relay with the line-up Gardener, Campbell, Devonish and Mark Lewis-Francis won gold with a hundredth of a second ahead of the USA.
In 2005 at the World Championships in Helsinki , the British relay won bronze with Gardener, Devonish, Malcolm and Lewis-Francis. In 2006 at the European Championships in Gothenburg , Devonish repeated his third place from 2002 over 200 meters. The season won gold with Chambers, Campbell, Devonish and Lewis-Francis. At the 2007 World Championships in Osaka, he was sixth over 100 meters and won bronze with the relay.
Marlon Devonish has a competition weight of 72 kg with a height of 1.80 m.