Wallace's managership of Rangers saw the club achieve a period of sustained success. His first season as manager - the club's centenary year - culminated in a 3-2 Scottish Cup win over Celtic.
A nine-year period of Celtic dominance in the league was ended in 1974-1975 as Rangers captured what was to be the last championship of its kind. The new ten-team Scottish Premier League saw Rangers crowned inaugural champions, as part of a triumphant domestic treble. After a barren subsequent season, 1976-1977, Wallace presided over the club's fourth domestic treble in 1977-1978.
This burst of success from the mid-1970s saw Rangers once again established as Scotland's most successful club. In 1978 Wallace, suddenly and unexpectedly, announced his resignation while refusing to divulge the reason for his departure. In his wake, Rangers turned to another of the stalwarts of the great side of the mid-to-late 1970s, the captain John Greig.