Playing in the NHL was somewhat of a family affair for the McCreary family. Bill McCreary's father Bill played with four NHL teams before getting into coaching, where he also made four NHL stops. McCreary's two uncles Keith McCreary and Ron Atwell also played in the NHL as did his cousin Bobby Atwell.
McCreary played with the Cleveland Junior Barons for two years before enrolling at Colgate University where he played for two years. "I felt it was the safest route," McCreary noted. "With an education, you always have something to fall back on." He was selected by the Toronto Maple Leafs in round six of the 1979 NHL Entry Draft, 114th overall. He did manage to get into the Toronto lineup for 12 games in 1980-81 which turned out to be the only 12 of his NHL career. He managed to post one goal. He is perhaps best remembered for a bone-jarring open-ice hit on Edmonton's Wayne Gretzky, which left number 99 lying stunned on the ice for several moments. It was big news at the time as nobody had ever managed to connect with such a thundering check on Gretzky. If there was an unwritten rule in the NHL stating Wayne Gretzky was not allowed to be hit, nobody mentioned it to McCreary.
In spite of the great family hockey heritage, Bill Jr always maintained he never faced pressure from his family to follow in his father's footsteps. "Dad never pushed me, never made me play," McCreary said. "When I had a bad game he never cut me down. But he was always there when I needed him."
McCreary continued to play hockey for another seven NHL seasons, all in the minors. While he was a solid all-round player, he just seemed to lack that final push to enable him to reach the NHL. Most of his pro career was spent in the IHL, including the last five years of his career with the Milwaukee Admirals. He decided to hang up the skates following the 1987-88 season at the relatively young age of 28.