Born in Georgetown, Guyana Allen emigrated to Canada, first to Brampton where he attended Turner Fenton Secondary School, and then to Malton where he went to Ascension of Our Lord Secondary School. He competed for Guyana in the 2000 Summer Olympics, and still holds the Guyanese record in the 110 meter hurdles. Switching to the Canadian team for the 2004 Summer Olympics he made the finals in the 110 meter hurdles after setting a new personal best time in each of the qualifying rounds. Finishing a respectable sixth, but in a slower time than he had hoped. He was also captain of Canada's 4x100 relay team, but the team failed to pass the qualifying stages. At the 2006 Commonwealth Games in Melbourne, however Allen, won a bronze medal with the Canadian relay team.
As a hurdler he is known for knocking down the majority of the hurdles during his sprint.