Clarke played for Team Canada three times during his career. He played a major role in defeating the Soviet Union during the Summit Series in 1972, captained the Canadian team to gold at the 1976 Canada Cup, and won a bronze medal at the 1982 World Championships. In addition, he led the Flyers to the only outright victory over the Soviet Union's best team, Soviet Red Army, during the 1976 Super Series, and took part in the 1979 Challenge Cup with the NHL All-Stars. After his playing career, he served as one of Canada's four general managers during the 1987 and 1991 Canada Cups and served as Canada's lone general manager during the 1998 Winter Olympics.