Prodigious from a young age, he ran the fastest 400 m times ever by a 14-year-old and a 15-year-old. He won a series of gold medals at the CARIFTA Games and the Commonwealth Youth Games and rose on the international stage with 400 m silver medals at the 2007 World Youth and 2008 World Junior Championships. James became the first athlete to run a 200/400 double at the 2009 World Youth Championships and was the 2010 World Junior Champion.