Mullings began his international
athletics career with a bronze medal win in the 100 m at the
Pan American Junior Championships. At the 2004 national championship he made his first impact in senior athletics, setting new bests of 10.04 and 20.22 in the sprints, and finishing as the 200 m national champion. This earned him qualification into the
2004 Summer Olympics, but he was withdrawn from the competition after his sample from the national championships tested positive for banned substances. After his B sample also tested positive for
testosterone, he was banned from competition for two years and his results between mid-2004 and 2005 were removed from the record. He returned to competition in 2006 but finished the season with unimpressive bests of 10.31 and 20.54. The following year was much more successful. He won the 100 m in
Zaragoza with a wind-aided (3.7
m/s) run of 9.91 seconds, and featured on the
2007 IAAF Golden League circuit. He competed at the
2007 World Championships in Athletics as a heats runner for the Jamaican silver medal-winning
4 × 100 metres relay team. After an uneventful 2008, Mullings returned to form in 2009. He placed second over 200 metres in the national championships behind Olympic champion
Usain Bolt. He set new personal bests in both sprints in July, running 20.01 seconds over 200 m in
Rethymno, and 10.01 seconds over 100 m at the
Golden Gala. Competing at the
2009 World championships in
Berlin, Mullings finished 5th behind Bolt in the
200 m in a personal best time of 19.98 seconds and won his first global gold medal as part of the successful Jamaican
4 × 100 metres relay team, running in both heats and the final. In 2011, he broke the 10 second barrier for the first time at age 28, and by the end of the year had run under 10 seconds seven times. ==Lifetime ban for doping violations==