At that stage he was largely playing on the wing for the Scarlets, yet still got picked for Wales. But then a switch to the Ospreys in 2006 with the chance to play full back changed the course of his rugby life.
Since then it has been a steady progression in the right direction. There have been titles with the Ospreys, a Grand Slam with Wales and then a call up for the British & Irish Lions.
But there is one thing Byrne still craves - a place in the Lions Test team to take on the world champion Springboks this month. He gets his latest chance to prove his worth to head coach Ian McGeechan against The Sharks in Durban tonight.
With just 10 days to go to the first Test he knows it is time to deliver and show he can fit in with likely Test centres Brian O'Driscoll and Jamie Roberts.
"There were times when my career looked like it was going nowhere. But, as I've said before, Warren Gatland gave me a chance and I have never looked back," said Byrne.
"The Ospreys approached me and said that I could be their first-choice full back, which offered me more game time. I thought why not give it a crack."
Byrne starts his third game on tour at the Absa Stadium tonight and appears to be in pole position to hold off the challenge from Leinster's Rob Kearney for the No 15 jersey against the Boks next week.
Having seen players like Jack Matthews (1950), JPR Williams (1971 and 1974), Scott Gibbs (1993 and 1997) and Gareth Thomas (2005) all reach Test status from his home town of Bridgend, Byrne is keen to follow suit.
"I want to finish this season on a high. I did not really think I was favourite for the Test jersey, but it would be a dream come true if I got it," he said.
"To be on the tour was great, but to claim a Test jersey would take it to another level. This will probably be my last chance in a Lions jersey and that is why I don't want to have any regrets and look back on the tour and worry that I did not do everything I needed.
"I know that I have to be on top of my game. There is a big pressure to put down a marker for that Test jersey."
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