Toronto will now host the Seattle Sounders in the MLS Cup final on December 10.
Toronto, who had trailed 3-0 in last week's first leg in Montreal before recovering to score two crucial away goals, will now host the Seattle Sounders in the MLS Cup final on December 10.
A pulsating duel at a rainswept BMO Field was effectively settled in the first half of extra-time, when goals from Benoit Cheyrou and Tosaint Ricketts put Toronto 5-2 ahead on the night, 7-5 on aggregate.
"It was a crazy match. The score line alone at 5-2 in a conference final was amazing," said Ricketts, a Canadian international who joined Toronto in July.
"I'm so proud of the guys. We battled back many times in the game and showed so much character. It was a very special moment for all of us."
The defeat marked the final chapter of Didier Drogba's MLS career. The former Chelsea and Ivory Coast star is leaving Montreal in the close season.
The extra-time drama came after an action-packed 90 minutes which saw Montreal take a 1-0 lead -- 4-2 on aggregate -- with a swift counter-attacking goal midway through the first half.
Patrice Bernier outmuscled Toronto's US international captain Michael Bradley near halfway and quickly released Matteo Mancosu, who in turn picked out Dominic Oduro.
The veteran Ghanaian striker darted into the box and tucked away a low finish past Clint Irwin.
Toronto, however, were handed a lifeline on 37 minutes when a Sebastian Giovinco corner was met with a powerful header by Nick Hagglund.
Hernan Bernadello cleared off the line but only as far as Armando Cooper who lashed home the rebound.
Cooper might have had a penalty moments later, when he rounded Montreal goalkeeper Evan Bush.
But instead of going to ground Cooper stayed on his feet and penalty appeals were waved away by referee Jair Marrufo.
On the stroke of half-time, though, Toronto took the lead, and again it came from a setpiece, Giovinco curling an outswinging corner to the near post where an unmarked Jozy Altidore glanced in a firm header.
"It's fantastic," Altidore said of Toronto's run to the title match -- a first for a club that until this year had never notched a playoff win in its 10-year existence. "It's all for the fans. They've suffered a long time. After the type of season we've had this year, hopefully we can give them one more celebration."
The momentum appeared to be firmly with Toronto but within eight minutes of the restart, Montreal were back in front on aggregate when Ignacio Piatti bundled in a scruffy low finish to make it 2-2 on the night.
Once again Toronto responded with a setpiece goal. A quick freekick allowed Justin Morrow to escape to the byline and the fullback's cross picked out Hagglund whose thumping header beat the diving Bush to make it 3-2 and 5-5 on aggregate, ultimately sending the tie into extra-time.