After two seasons of junior hockey in his home country Sweden, Patrik Sundstrom represented his country at the World Junior Championships in 1980 where the team won a bronze medal. This year also saw Sundstrom drafted by the Canucks. He joined his twin brother, Peter, in the World Juniors the next year where he led the team to a gold medal and was named the tournament's best forward.
The 1981-82 season saw Sundstrom play in Sweden where he was named the Swedish player of the year as well as representing Tre Kronor in the Canada Cup and World Championships. He made his NHL debut in the 1982-83 season with the Canucks where he played for five seasons.
In 1987, Sundstrom was traded to the Devils where he stayed for the remainder of his career. Sundstrom was a part of the 1987-88 team that made a run for Lord Stanley's Cup, but the Boston Bruins who took the series in the seventh and deciding game stopped the team in the conference finals. Sundstrom retired from the game at the end of the 1991-92 season.