He played college hockey for the University of Minnesota from 1967 to 1970 and then represented the United States at the 1971 World Championship. He then played minor pro hockey until 1974 when he signed with the Minnesota Fighting Saints of the World Hockey Association (WHA). Westrum played in the WHA through the 1977-78 season. He scored 7 goals and 45 assists in 237 games. He played two more seasons of minor pro and retired in 1980. Westrum is now the Minnesota scout for the Montreal Canadiens after serving in the same position for the Phoenix Coyotes.