Toronto-born Mark Osborne found an important role with the Maple Leafs after previous successful stops in Detroit and New York. Osborne became an effective two-way left-winger over two separate tenures with the Leafs. Obtained from the Rangers late in the 1986-87 season, Osborne led the Leafs with 37 assists in his first full Toronto season in 1987-88. The line of Osborne, Ed Olczyk and Gary Leeman proved to be a dynamic scoring trio until Osborne and Olczyk were dealt to Winnipeg in 1990. Osborne was later reacquired by the Leafs near the end of the 1991-92 campaign.
Under the coaching of taskmaster, Pat Burns, the club advanced to consecutive conference finals in 1993 and 1994. Osborne combined with linemates Peter Zezel and Bill Berg to provide a tight-checking but opportunistic scoring line as the Leafs earned 99 points in the standings in 1993 and 98 points in 1994.
Osborne collected 30 or more assists three times as a Leaf and his most productive NHL output was on the highest-scoring team in Leafs' history in 1989-90. That season, he lit the lamp 23 times and added 50 assists for 73 points to place fifth in team scoring.
He recorded 94 goals, 160 assists, 254 points and 563 penalty minutes in 426 games with Toronto.