Matteo Codispoti, who runs the We Want a Cup website, said the series is an important event for Toronto fans and the members of his family.
"As a Leaf Nation member, it’s the end of the nine-year drought — the longest drought in the NHL, our longest drought in our 100-year history," Codispoti told CBC Radio's Metro Morning on Monday.
"As a dad, I get to share moments with my kids. And as the son of a Leaf fan and the father of a Leaf fan, it’s big for me."
Toronto has split the first two games of the series with Boston, which is the first time the Original Six rivals have met in the post-season since 1974.
The Leafs won the second game, which Codispoti said "captured the imagination of all of us."
That enthusiasm could be seen on the streets of Toronto on Monday, which Mayor Rob Ford proclaimed as "blue and white day" in the city.
"The thrill of playoff hockey is in the air in this great city folks," Ford said. "The Toronto Maple Leafs' long journey back to the playoffs is finally over."
The mayor, wearing a Leafs jersey, predicted Toronto would capture the series by winning the next three games.
Ford said he saw many wearing blue and white along Bay Street.
The Leafs themselves have taken notice of the spirit in the street.
"Even before we were in the playoff run, that's just Leaf Nation — they're everywhere," said Toronto forward Nazem Kadri.
"We've got the best fans in the world and we're expecting to see it tonight."
Couple decorates house in Leafs colours
While fans celebrated downtown, one Toronto couple is taking their love of the Maple Leafs to the street.
The exterior of Michael and Sara Adamson’s house on Merton Street, near Bayview Avenue, is draped in blue and white in honour of the Leafs, who play their first home playoff game in nine years tonight.
The Adamsons' shrine to the Leafs includes a massive banner draped over the roof, a Leafs hockey helmet and a Curtis Joseph hockey stick.
"People are honking a lot, a lot of people taking pictures and a lot of people really happy about it," Michael Adamson told CBC News.
Adamson's wife Sara says Leaf Nation is rallying support.
“We had to wait nine years after the last playoffs and here we are again.”
The couple says they've heard only one complaint about their display of devotion to Toronto’s team, but that came from a Bruins fan.
Ahead of Monday evening's game, there were occasional sightings of Bruins supporters on downtown streets.
The CBC's Genevieve Tomney tweeted that she saw one Boston fan get heckled on a subway train for showing her support for the rival team.