Orr played in 44 of 48 regular-season games for Toronto this past season and led the league in penalty minutes with 155. He added one goal and three assists and had a plus-4 defensive rating.
He earned his 1,000th career penalty minute on March 21 Buffalo.
He played in all seven of Toronto's playoff games, putting up 18 penalty minutes.
The six-foot, 222-pound Winnipeg native joined the Maple Leafs as a free agent on July 1, 2009.
Originally signed by the Boston as a free agent before the 2001-02 season, Orr has 12 goals, 12 assists and 1,076 penalty minutes over 10 seasons with Boston, the New York Rangers and Toronto.
The Leafs also announced the signing of goaltender Drew MacIntyre to a one-year, two-way contract.
MacIntyre, 29, played in 21 games for the Toronto Marlies of the American Hockey League this season, posting a record of 13-5-3 with a 1.83 goals against average and a 0.931 save percentage.
The Charlottetown native went 5-4 in the Calder Cup playoffs with a 2.85 GAA and a 0.913 save percentage.
MacIntyre has played the bulk of his career in the minors, but he has appeared in four N-H-L games with Vancouver and Buffalo.