The 40-year-old, who also represented New South Wales in State of Origin, will assist head coach Brian McDermott and trainer Sean Rutgerson with the American team.
The US team, known as the Hawks, will be one of the outsiders for the World Cup and you can bet with Betfair throughout the competition.
Kimmorley retired from playing in 2010, and has since worked as a coach at Canterbury Bankstown Bulldogs and Canberra Raiders.
He has also been the head coach of the Wests Tigers NYC team.
“Brian is a very successful Coach in the Super League and I look to educate myself from the time we spend together,” said Kimmorley, currently coaching Wests Devils.
“I look forward to sharing my knowledge of the game and assisting the players with their performance not only in the World Cup, but also when they return to America.
“I have played in a World Cup and view it as the pinnacle of international game and will do my best to achieve the best results that we can.”
McDermott is delighted that Kimmorley is on board with the American squad.
“Getting Brett Kimmorley on board with the coaching staff is fantastic news,” he said.
“Practically speaking, Brett will add a dynamic to our coaching staff that will certainly give us an edge in planning, prep and practice.”