He and Börje Salming combined to make one of the best 1–2 defensive punches in Toronto Maple Leafs history during the 1970s.
In his best offensive season, (1976–77 while with the Maple Leafs), he set career highs with 22 goals, 57 assists, 79 points, and a +47 plus/minus rating.
[3] Turnbull was outstanding in the 1978 playoff series against the New York Islanders, eventually won by Toronto 4 games to 3, anchoring the team’s defensive corps after an eye injury forced all-star defenceman Börje Salming out of the Maple Leafs line-up.
Early in the 1981-82 season, Turnbull was traded to the Los Angeles Kings in exchange for veteran forward Billy Harris and defenseman John Gibson.
[citation needed][4] Turnbull joined the Penguins for the 1982-83 season but played just six games for them before a back injury forced him out of the lineup and into retirement.