After switching to the "junior" age group in 2001, Brown won the 100 metres for three consecutive years (2001–2003), becoming the first athlete ever to do so.

Under the guidance of Henry Rolle Brown ran the 100 m at the 2003 World Championships where he finished second behind Kim Collins.

In the relay event, however, he won a silver medal with the Trinidad and Tobago team in a new national record of 38.10 seconds.

He competed at the 2008 Beijing Olympics, reaching the quarter-finals of the 100 metres, but he pulled up in the race, finishing in 10.93 seconds.

At the 2009 World Championships in Berlin, he competed as part of the 4 × 100 m relay for Trinidad and Tobago which finished second behind Jamaica in a national record of 37.62s.