Born in Pencoed, Henson played rugby for his school, Brynteg Comprehensive, close to Bridgend, Wales. He then started his next match, at fly-half in a game against Romania in September. in November of that year he played for Wales A against Uruguay, scoring his first try in an international. He made his debut for the Ospreys as a substitute on 9 September 2003 in a match against Ulster, scoring two tries and kicking both a penalty and conversion to score 15 points. He remained on the team for the 2005 Six Nations championship. He was found not guilty of the kicking offence, but guilty of the elbowing. He was initially suspended for ten weeks and two days: this period was reduced on appeal to seven weeks. Following this suspension and a single game at club level, he returned to international rugby against Ireland.
