The 28-year-old linked up with the Welsh region yesterday at their Ystrad Mynach training base, as they prepared for their Guinness PRO14 clash against Ulster this weekend at the Kingspan Stadium.
The versatile player, who can play in the centre and on the wing, joined Bristol in 2016/17 and will add support to the Dragons backline due to the recent injury toll suffered.
The American international represented USA during the 2007 Rugby World Cup, becoming the youngest player in history to feature in the tournament at that time.
Dragons head coach, Bernard Jackman commented: “He is a really good athlete, he is powerful and strong and has been surrounded by good environments since he was with Saracens as well as during his time in the American sevens programme for the Olympics.
“I know him from when he was with Saracens and he’ll be a good addition to the squad, I look forward to seeing him play. He will be included in the match-day 23 for Ulster.”