Smyth debuted with Hockey Canada with the country's under-20 team at the 1995 World Junior Championships in Red Deer, Alberta. He recorded two goals and seven points as Canada went undefeated in seven games to win the gold medal. Four years later, Smyth was chosen to the Canada's men's team for the 1999 IIHF World Championship in Norway. As a result of the Oilers' short playoff seasons (the team made the second round twice and Finals once in his 12-year tenure), Smyth was a mainstay on Canada's World Championship roster (the international tournament conflicted with the NHL's playoff schedule). The 1999 tournament marked the first of seven consecutive appearances for Smyth. He recorded two assists over nine games as Canada finished in fourth place, losing the bronze medal game to Sweden.