He played junior hockey for the London Knights. Zanussi was then drafted in the 3rd round, 51st overall, by the Minnesota North Stars in the 1976 NHL Entry Draft. He turned pro with the Fort Wayne Komets of the International League in 1976-77 and shared the Gary F. Longman Memorial Trophy as rookie of the year. Zanussi then made the jump to a regular spot with the North Stars the next season, keeping that spot until he was traded to the Toronto Maple Leafs in Marhc, 1981. In 299 NHL games, Zanussi scored 52 goals and 83 assists.