Tkaczuk centred the "Bulldog Line" with Bill Fairbairn and Dave Balon, who was later replaced by Steve Vickers.

Tkaczuk's finest contribution to the game was that of the defensive forward, being among the NHL's elite shadows and faceoff men.

[3] In the 1972 playoffs, with Ratelle sidelined with a broken ankle and Gilbert hampered by injuries, Tkaczuk played a key role as the Rangers defeated the defending champions Montreal Canadiens, and the previous season's finalists Chicago Black Hawks, to reach the Stanley Cup Finals.

Tkaczuk was asked to play for Team Canada in the 1972 Summit Series but declined the invitation due to his obligation to his summer hockey school.

[4] In the 1979 playoffs, Tkaczuk was a key contributor as the Rangers upset the first place New York Islanders to reach the Stanley Cup Finals, where they fell to Montreal in five games.