It's a UN team. The guy of whom you speak is part of the Canadian contingent. There are also Russians and Germans who have had a part in the show.
Didn't know that because I remember him when he first showed up on Stargate SG1 episode. He & Carter tried to rid the Comand Center from one of Anubis' plot to blow the earth up. He played a know it all dweeb that downplayed Carter's achievements. Nothing indicated that he was Canadian. Then he shows up as a regular on Stargate Atlantis with the same "I'm smarter than you, you pathetic creature" attitude.