Collins holds a personal best of 9.93 seconds for the 100m, which is a Saint Kitts and Nevis national record and a M40 world record for men over 40. This makes him the only man over forty years of age to break the 10-second barrier. His indoor personal best of 6.47 seconds for the 60m is a national record and a M35 world record.[2][3]
Collins competed in college for Texas Christian University.[5] He competed on behalf of his country in the 1996, 2000, 2004, 2008, and 2016 Summer Olympics.[6]
Collins made his debut at major championship at the 1996 Olympics, where he qualified for the second round in the 100m. He improved quickly, and at the 2000 Summer Olympics, he became the first athlete from his nation to qualify for an Olympic final, finishing 7th in the 100m. The next year, Collins would win St. Kitts' first World Championship medal, when he tied for the bronze medal in the 200m.
At the 2002 Commonwealth Games, he won his first major title. After the 100 m race, which Collins won after two other favourites pulled out of the final with injuries, he failed a doping test, testing positive for the beta agonist Salbutamol.[7] However, it was found that the banned substance was part of the asthma medication Collins had been taking for several years, but had neglected to mention to the medical commission. Collins eventually was allowed to keep his title, and got away with a warning.[8]
Collins was featured on a set of two stamps from St Kitts issued in 2002.[9]
The 100m at the 2003 World Championships became the biggest triumph of his career. With Olympic and World Champion Maurice Greene eliminated in the semi-finals, the field was wide open. In a very close race, where the top four athletes finished within 0.02 seconds, Collins won and became the first world champion from Saint Kitts and Nevis.
Finishing fourth in his heat, Collins qualified for the finals in the men's 200m race in the 2008 Beijing Olympics and finished in sixth place on 20 August 2008. He competed at the 2009 World Championships and reached the quarter-finals of the competition, but he was eliminated after finishing in fourth place behind eventual finalists Asafa Powell, Darvis Patton and Marc Burns. He announced his retirement from international athletics in September that year, bringing an end to a career that spanned almost 17 years.[10]
Collins returned to athletics on 29 January 2011 at the Aviva International Match in Glasgow, reversing his retirement at the age of 34, and he finished fourth in the 200 metres. He then won at the Russian Winter Meeting in Moscow.[11] He set a 60m personal best and national record of 6.52seconds to win at the PSD Bank Meeting in Düsseldorf, overhauling his best mark which he had set nearly eleven years earlier.[12] That time did not stand for as long, however, as he ran 6.50seconds in the heats of the BW-Bank Meeting a few days later.[13] Collins won both his heat and semi-final races in the 100 m at the 2011 World Championships before finishing third and winning a bronze medal in the final after the disqualification of Usain Bolt.[14] At the men's 4 × 100 m relay qualifying heats, Collins ran the second leg for the St Kitts and Nevis relay squad and helped clock a national record of 38.47, leading to St. Kitts and Nevis' first-ever final. The last event saw Collins team up with Jason Rogers, Antoine Adams and Brijesh Lawrence to clock 38.49 to win the bronze medal.[15]
At the XVI PanAmerican Games in Guadalajara 2011, Collins broke the 28-year-old PanAmerican Games record with a time of 10.00 in the early heat. He finished second in the finals to Jamaica's Lerone Clarke. His silver medal was the first-ever medal for St. Kitts and Nevis at the Pan-Am Games.[16][17]
Collins was expelled by his team from the 2012 Summer Olympics in London on 4 August 2012 for missing training sessions. He said he was being punished for spending time with his wife.[18]
Collins was the oldest sprinter at 2016 Summer Olympics, his fifth consecutive appearance at the Olympics. While most sprinters peak in their 20s, Collins set his personal record after reaching the age of 40, and became the first individual to run a sub-10 second 100m dash in the process. He ran a 9.93 100m dash, which was fast enough to qualify for Rio de Janeiro.[19] He competed in both the 100m sprint and 4 × 100m relay.[20] Collins was the only St. Kitts and Nevis athlete to make it out of the first round. He finished his heat with a time of 10.18 and fourth place. He improved his time in the semifinals, finishing with a time of 10.12. This put him in sixth place and he did not advance to the finals.[21]
In 2018 Collins announced his retirement, he competed at the 60 m at the 2018 IAAF World Indoor Championships. His last performance at a World Championship.
25 August was declared Kim Collins Day by the government of St. Kitts and Nevis in honour of Collins’ gold at the World Championships in Paris, France in 2003.[22]