McKechnie was drafted sixth overall by the Toronto Maple Leafs in the 1963 NHL Amateur Draft of 16-year-old players. He played junior hockey with the London Nationals from 1965 to 1967 before turning professional with the Phoenix Roadrunners of the Western Hockey League (WHL) in the 1967–68 season, where he was named the league's rookie of the year. In February 1968, he was acquired by the expansion Minnesota North Stars and played four games in the NHL regular season followed by nine playoff games. For the next three years, he split his time between the North Stars and their minor league affiliates.