Campbell was a promising junior athlete and won a number of medals at the World and European Junior Championships. He spent two years away from athletics, playing professional football but returned in 1995, attending his first Olympics shortly afterwards. He began to compete as part of the British 4 × 100 m relay team and between 1997 and 2000 he won two World Championship medals, a gold medal at the 1998 Commonwealth Games, and set the European record in the event. Success also came in the individual events: he became the 1998 European Champion in the 100 m and won his first Olympic medal, a silver in the 200 m at the 2000 Sydney Games. In the 100 m he won silver at the 2002 European Championships and was the 2003 World Championships bronze medallist.
Campbell formed part of perhaps Britain's most successful relay team – they won in the European Cup in 1999 and 2000, at the 2002 Commonwealth Games, and took the gold at the 2004 Athens Olympics (the first time a British team had done so since 1912). Campbell had also won a gold medal at the 2002 European Championships and a 2003 World Championship silver medal but had to return them when his running-mate, Dwain Chambers, tested positive for banned substances, sparking much animosity between the two. He won his last medal in 2006, again taking the relay gold at the European Championships, and he retired shortly afterwards. His personal bests of 10.04 s in the 100 m and 20.13 s in the 200 m—were not prodigiously quick by elite global standards, but over his career he earned an impressive reputation as a 'championship' runner, saving his best for finals and collecting significantly more medals than his times alone would indicate.
He now works with various Premier League football clubs, working with the players to improve their sprinting ability. He also regularly visits schools to promote sport among children, on behalf of the Youth Sport Trust, and he also recently appeared as a VIP guest at Sheffield Hallam University's annual Sports Ball held at Ponds Forge International Sports Centre.
Campbell was a talented athlete and footballer in his youth. His first national success in athletics was a gold medal at the English Schools Championships in the 200 m. Campbell then won the 100 m and 200 m gold medals at the 1991 European Junior Championships held in Thessaloniki, Greece, as well as a gold medal in the 4 × 100 m. A year later, he won silver medals at the 1992 World Junior Championships, in the sprint double, and a gold medal in the 4 × 100 m relay. He was beaten both times by Ato Boldon, who became the first athlete to win a double at the championships. His senior international debut came at the Stuttgart World Championships in 1993, as part of the 4 × 100 m squad. However, as a result of injuries, he left athletics at the age of 21 to launch a career in football with trials for Cwmbran Town, Plymouth Argyle, Yorkley, Weymouth, UWIC Inter Cardiff and Newport County amongst others. During a debate on TalkSPORT on 14 August 2006, Campbell stated this period away from athletics had also been spurred on by attempts by certain individuals to draw him into a drugs programme.
Campbell returned to athletics in 1995, and ran the 100 m in 10.34sec that year. The following year, he improved his 100 m time to 10.17sec, and represented Britain in the 1996 Summer Olympics in Atlanta, United States. Campbell only represented Britain in the 4 × 100 m relay, but did not receive the baton, as it was dropped before it reached him.
At the 1997 World Championships, Campbell won his first major senior medal - a bronze in the 4 × 100 m relay, and by this time was a regular feature in the British squad.
Campbell's first senior gold medals came at the 1998 European Championships in Budapest. Campbell won the 100 m individual event, setting his best time at the 100 m in the final - 10.13sec, and also winning gold in the 4 × 100 m relay. At the Commonwealth Games that year, Campbell helped break the championship record for the 4 × 100 m relay. However, he won no individual medals.
The following year, in the 1999 World Championships, held in Seville, Campbell won the silver medal in the 4 × 100 m relay, but was eliminated from his individual event in the semi-finals.
In 2000, Campbell won the man of the match award in the European Cup following his performance in the 100 m. Campbell replaced Jason Gardener with 20 minutes notice, and won the race in a time of 10.09sec (wind-assisted). He also ran in a leg in the winning 4 × 100 m relay team.
At the Olympics in Sydney, Campbell placed 6th in the 100 m final, and took a surprise silver medal in the 200 m, as Campbell was mainly a 100 m runner, and had a previous best time of 20.49sec. In the quarter-final, he took 0.29sec off this to reduce to 20.13sec, his fastest time at the distance in his career. This was followed by performances of 20.23sec in the semi-final and 20.14sec in the final to finish second, Campbell's first senior medal at the distance. The gold medal was won by controversial Greek sprinter Konstantinos Kenteris
Campbell was again hit by injury in 2001, missing the majority of the year's competitions. He had run 10.16sec for the 100 m and 20.41sec for the 200 m, and been named European Cup captain prior to the injury.
After returning from injury the following year, Campbell took bronze in the individual 100 m event and gold in the 4 × 100 m relay at the 2002 European Championships. His bronze was later upgraded to a silver after Dwain Chambers confessed to taking performance-enchancing drugs at this time. However, the relay gold was later taken from him, as Chambers was part of the quartet. He won his quarter-final in the 200 m, but was eliminated after being disqualified for stepping outside his lane.
The year also saw Campbell compete in his home town of Manchester in the Commonwealth Games. He did repeat his Olympic success in the 200 m, receiving bronze in this event. However, he anchored the team to gold in the 4 × 100 m relay along with squad members Jason Gardener, Marlon Devonish and Allyn Condon, just beating Asafa Powell of Jamaica in a very tight photo finish.
In 2003, at the Paris World Championships, Campbell took bronze in the 100 m, but missed on a medal in the 200 m, finishing fourth in the final. He also ran the 2nd leg for the 4 × 100 m relay team, but later lost this medal due to Dwain Chambers being found guilty of doping. Campbell also set his 60 m PB of 6.59sec this year.
In the 2004 Summer Olympics, Campbell won a surprise gold medal in the 4 × 100 m, in a team with Jason Gardener, Marlon Devonish and Mark Lewis-Francis, who defeated the United States team by just 0.01sec, winning in a season's best of 38.07sec. However, Campbell performed less well in the 100 m and 200 m, exiting in the heat and semi-final respectively, due to not being fully recovered from a hamstring injury.
He was named captain for the European Cup in 2005, however did not have a successful season, only placing 5th in the AAA semi-final and running 10.47sec (10.48w) for the 100 m and 20.9sec for the 200 m. He did, however, receive an MBE in the New Year Honours.
Campbell competed at the 2006 Commonwealth Games in Melbourne, however did not progress past the semi-final in the 200 m, and the England team were eliminated in the 4 × 100 m after a faulty baton changeover in their heat. He did not compete individually at the European Championships in Gothenburg, but ran the second leg to help Britain to the gold medal in the 4 x 100 relay.
On 13 August 2006, after winning the 4 × 100 m European relay gold medal with Great Britain, Campbell left the track without completing a lap of honour with the rest of his team mates. He initially remained cryptic about his problems, but revealed the next day that his lap of honour boycott was due to his loss of two relay medals (2002 European Championships gold and 2003 World Championships silver) as a result of Dwain Chambers' doping. Campbell did, however, explain that he did stand by Chambers insofar as he was not solely accountable, but he felt Chambers had a duty to inform the authorities of the individuals who led him to his departure to America and his resulting adoption of a drug programme. John Regis criticised Campbell for this stand, also noting that his coach (Linford Christie) had served a drugs ban.
Campbell defended himself, saying "I will not regret doing that. At times you have to stand up for what you believe", and also that he was concerned about youngsters ending up the same situation. He also defended his links with Christie, stating that he would not have remained with Christie if he thought he had cheated.
Campbell announced his retirement on 18 August 2006. His final race was at the inaugural Celtic Cup race in Grangemouth, where he won the 100 m competing as a guest. Campbell surprised Dave Collins and UK Athletics, who had been expecting him to retire following the two-day international athletics meeting at Birmingham taking place over the following two days.
In July 2007, Campbell was announced as the new ambassador for Sky Sports Living for Sport, a successful initiative run by the Youth Sport Trust in conjunction with BSkyB, which uses sport as a tool to re-engage young people who may be at risk of opting out of school life. Sky Sports Living for Sport, now in its fifth year, has involved over 600 schools and benefited over 17,000 young people aged 11–16. Campbell's role will see him meet young people and teachers involved in Sky Sports Living for Sport across the country to share his experiences and help inspire them to reach their full potential.
Campbell is well regarded in football circles; he has given training sessions to Manchester United, Chelsea and Everton. He is said to be a pace and acceleration specialist. Campbell also worked with MK Dons, at the invitation of then manager, Paul Ince.
"When you look at some of the other big Premiership clubs, it looks as if they are doing the same kind of thing. As a Manchester United fan, I have noticed that their players run very efficiently. Arsenal's players are the same. But there are usually improvements you can make. The only player I don't think I could improve would be Thierry Henry. His technique is already up there. He could easily be a sprinter, and is the template I use with other footballers."
He has also been engaged by several professional rugby clubs such as Sale Sharks and Saracens to help develop the power and speed of the squad for the 2011–12 season. He has also previously worked with Jonah Lomu while the Kiwi was playing rugby for Cardiff.
Campbell's reputation was made as a championship runner, rather than a runner of fast times. Although he never raced below 10 seconds for 100m, or 20 seconds for the 200m, he consistently outperformed rivals with faster personal and seasons bests, enabling him to pick up medals at global and continental championships, and was an excellent, and consistent, relay runner. His medal record of Olympic gold and silver, and World Championship silver and bronze left him second only to Linford Christie among post war British sprinters in terms of global medals.All information taken from IAAF profile.
As well as these performances, during his career Campbell has also won seven national titles at either the 100 or 200 metres.