The Welsh International signed a two-year deal with the men of Gwent meaning that he will stay with the region until May 2016.
Before signing for the Dragons Byrne was associated with Top 14 French team Clermont Auvergne and has been rated amongst the best fullbacks in the world.
Director of rugby, Lyn Jones commented: "Lee's ability as a player is outstanding; he has great leadership skills and has a lot of experience behind him.
"Andrew Coombs captained the side very well last season, but I feel that this is a season that I need apply change throughout which will also allow Andrew to focus on his international career."
On becoming skipper of the Welsh region for the 2014/15, Byrne added: "It's probably one of the best pieces of news that I have ever had. Throughout my rugby career I have had both highs and lows, and this for me is right up there in the highs.
"Becoming captain of the Dragons will be a massive challenge for me, but now it's time for us to make sure that we deliver as a team. We have been given the best of everything this season, including the squad, coaches and the new training facility."I want to lead by example and I hope that the youngsters can learn from my attitude and the experience that I have gained through my international career and through playing in France."
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