Harrison played for the major junior Estevan Bruins (a Boston Bruins farm team) of the WHL from 1964-68. He was known as a hard-hitting goal scorer. He was picked up as a reinforcement for the Edmonton Oil Kings when they won the 1965-66 Memorial Cup Final. He turned pro in 1968 with the Bruins but was quickly traded to the Toronto Maple Leafs for Wayne Carleton in 1969. With Toronto, Harrison was expected to be a tough player with little chance to score goals, He filled that job but was unhappy at not being given the chance to be a scorer.