Toronto made its debut in the NHL on December 19, 1917 as the Toronto Arenas and suffered a 10-9 loss at the hands of the Montreal Wanderers as a mere 700 spectators looked on. The team got its name because it was owned by the Mutual Street Arena. Despite this loss, Toronto won the Stanley Cup in their first year during the second half of the split season, defeating the Vancouver Millionaires of the Pacific Coast Hockey League in a best of five series. This however, was not the first time the Stanley Cup had been in Toronto. The Toronto Blueshirts of the National Hockey Association had won the cup in 1914 over the Victoria Cougars in a best of five series.

On February 20, 1919, the Toronto Arenas withdrew from the league, almost ending hockey in Toronto, but were back for the 1919-20 season as the Toronto St. Patricks. 1922 saw the St. Pats group shock the hockey world by defeating the Ottawa Senators and then the Vancouver Millionaires to capture their second Stanley Cup. This series also saw the awarding of the first penalty shot in Playoff history. Babe Dye was awarded the shot after being tripped by Art Duncan, but missed.

In 1923 a reporter for a local newspaper began broadcasting hockey games from the Mutual Street Arena. His name was Foster Hewitt, and it wouldn't be long before we all heard the words, "He shoots, he scores!" from radios and televisions on Saturday nights.

Conn Smythe was fired from the New York Rangers in 1926 and vowed to put a team together that could defeat the Rangers, and in February of 1927 he purchased the St Pats for $160,000 and immediately renamed the team the Toronto Maple Leafs. At the same time he changed the team colours from green and white to the blue and white we know today.

With the success of Hewitt's broadcasts, Smythe realized that the Mutual Street Arena would not be able to hold the crowds that were turning out to watch the leafs and he began to put together plans for Maple Leaf Gardens. Smythe traded Garden's stock to the trades and the new facility was build in less than six months for the sum of $1.5 Million. In 1931-32, during their first year in the Gardens, the Leafs beat the New York Rangers to bring home the Stanley Cup.

On December 12, 1933, at the Boston Garden, Ace Bailey, one of the Leafs star players was severely injured by Boston's Eddie Shore, and had to undergo emergency brain surgery to save his life. Bailey recovered, but was never able to play hockey again. Two months later a benefit game was played at the Gardens where Bailey walked to centre ice to shake hands with Shore. This game became the forerunner to today's All Star Game. On April 3, 1933 the Leafs and Red Wings played what would turn out to be the longest playoff game ever played in the building, over 5 overtime periods were played before Ken Doraty scored the lone goal of the game.

In 1940, Dick Irvin resigned as coach and was replaced by Hap Day and almost immediately began to make his presence felt. In the 1942 playoffs, with his team down 3-0 in games against Detroit, Day made some player changes and pushed his team to 4 straight victories, the only time any team has come back from a 3-0 game deficit in the Stanley Cup final. 1945 saw goalie Frank McCool hold his ground against the Detroit Red Wings setting a playoff record with 3 shutouts during the best of seven series that went to seven games. Babe Pratt was expelled from hockey in 1945-46 for betting on hockey games, but never on the games he played in. He was later reinstated by quickly traded from Toronto to the Boston Bruins. 1947 saw the leafs regain the Stanley Cup on Ted Kennedy's winning goal over the Montreal Canadiens. The next season Conn Smythe traded 5 players to land Max Bentley from the Chicago Black Hawks. Smythe's hunch worked and Toronto landed back to back Stanley Cups. Hap Day continued his winning ways and coached the team to 5 Stanley Cups in eight years. Only the Montreal Canadiens have ever equaled that record.

1950-51 will always be remembered for Bill Barilko's overtime goal. Toronto squared off against Montreal and every game of the series went into overtime. In game 5 it looked like Montreal would win it until the leafs pulled their goalie and Tod Sloan scored with only 32 seconds left in the game. At 2:53 of the first overtime period Barilko broke in from the blue line and put the puck past net minder Gerry McNeil. Tragically Barilko died a few weeks later in a plane crash. On February 1, 1955 at the age of 60, Conn Smythe retired and Hap Day took over the position of General Manager, and for the first time in their history, the Leafs finished in last place.

1958 saw the addition of Johnny Bower, Carl Brewer, Allan Stanley and Punch Imlach as coach and general manager. He added rookie sensation Dave Keon and the colourful Eddie Shack and managed to wrestle Red Kelly from Detroit in 1960. The Leafs reached the Cup finals that season, only to lose it to Montreal. The Leafs won the Cup in 1962 defeating the Blackhawks, again in 1963 beating Detroit and again in 1964 against Detroit. In the final game of the series, Toronto defenseman Bobby Baun netted the winning goal while suffering a broken ankle. 1967 would mark the end of the Original Six era, and the last time the Leafs would win the Stanley Cup. Imlach traded Frank Mahovlich, Terry Sawchuk and Carl Brewer.

Throughout the 1970's the Leafs played average hockey. One of the highlights came on February 7, 1976 when Daryl Sittler scored a record 10 points(6G, 4 A) and later that year in the playoffs scored 5 goals against Philadelphia as well as the overtime winning goal in the inaugural Canada Cup Series.

The '80s were perhaps the Leafs worst decade in their history. Coaches came and went, Roger Neilson, Joe Crozier, Mike Nykoluk, Dan Maloney, John Brophy, Doug Carpenter and George Armstrong, and even Punch Imlach returned for a short time. Players were traded, Sittler, Lanny McDonald, Tiger Williams, and Pat Boutette all left. Despite all this, Rick Vaive became the first Leaf player to score 50 or more goals in a season(54) and repeated the feat in each of the next 2 seasons. Gary Leeman also accomplished the same feat later with 51 goals. 1986 saw the passing of King Clancy and in April of 1990, Harold Ballard died, ending the Leafs link with the Original Six.

In 1991 Cliff Fletcher was hired as the president, chief operating officer and general manager. One of his first moves was to name Wendel Clark as captain and in 1992 he snagged Doug Gilmour, Jamie McCoun, Ric Nattress, Kent Manderville and Rick Wamsley from Calgary. Next he signed Pat Burns as coach in May of 1992. In the 1994 Mats Sundin was added to the team during the entry draft. Fletcher was let go in 1997 and replaced by Ken Dryden who said he would put a better product on the ice, and better hotdogs in the stands.