The 45-year old joins the Maple Leafs after a 27-year NHL career as both a player and league executive.
Since retiring from hockey in 2009, Shanahan served at the NHL's VP of Hockey and Business Development through 2011, upon which he jumped into his current role with the League.
Last summer, Shanahan rejected an offer from the Calgary Flames to become their President of Hockey Operations.
Drafted second-overall by the New Jersey Devils in the 1987 NHL Entry Draft, the native of Mimico, Ontario, won three Stanley Cups, all with Detroit, in 1996-97, 1997-98 and 2001-02.
In 1,524 career NHL regular-season games with the Devils, St. Louis Blues, Hartford Whalers, Red Wings and New York Rangers, Shanahan accumulated 656 goals (putting him 13th in NHL history) and 698 assists for 1,354 points, along with 2,489 penalty minutes.
On the International stage, Shanahan gold medals with Team Canada at the 1994 World Championships, the 2002 Winter Olympics and the 1991 Canada Cup.
He was inducted into the Hockey Hall of Fame on July 9, 2013.