The centre was an impressive performer for the Tomahawks in the recent competition, making three appearances and scoring one try.
He had trained with Super League side Hull but has now penned a deal with Tony Benson's ambitious Oxford side.
"I'm really excited about this season. We've got a strong squad and are very serious about winning, which I love," the 24-year-old said.
"I am personally looking forward to earning my spot within the team and I have got to earn the jersey spot first."
The Dallas-born back started his league career at Warrington - becoming the first American in Super League while he was there - and has also played rugby union with Fylde and Sale.