It was with the Bruins that the 5-foot-9-inch, 170 pound (77 kg) right wing had the most productive seasons of his career. He became a star in the 1967-68 season, scoring twenty-eight goals and gaining a reputation as a pesky, relentless hustler. He scored twenty-nine goals each of the next two seasons, and was named to the Second Team All-Star in 1969–70. In the playoffs that year he scored seventeen points in fourteen games, fourth on the team after Bobby Orr, Phil Esposito and John Bucyk and did so again in 1971-72. His best season was 1970–71, when he scored 31 goals and 77 points in 65 games. All in all, McKenzie scored 169 goals in his seven years in Boston and helped the Bruins win two Stanley Cup titles, in 1970 and 1972.