Aleksander Barkov and Jonathan Huberdeau also had goals for the Panthers (29-25-6).
Dominic Moore and Zach Hyman scored for the Maple Leafs (39-20-7).
Florida goaltender Roberto Luongo stopped 37 shots in improving his record to 4-1-0 since his return from injury.
Toronto backup goalie Curtis McElhinney had 28.
Aaron Ekblad flipped a backhanded pass into the neutral zone in overtime, and McCann skated in and fired the game-winning goal over McElhinney's blocker to give the Panthers their third straight win to open their six-game homestand.
The club finished February with a 9-3-0 record and is 10-3-0 in the last 13.
The two clubs met one week ago in Toronto as the Maple Leafs were victorious, 1-0, behind a goal from James van Riemsdyk and a shutout from Frederick Andersen.
On their second power play of the first period, Florida cashed in when Huberdeau slipped a pass from behind the Toronto goal to Barkov, who was standing near the post.
The All-Star center roofed his 21st goal over McElhinney at 11:02 for a 1-0 lead, giving him 16 points in his last 10 games.
Huberdeau skated through the slot past Tomas Plekanec, held the puck patiently and guided a nifty shot in for his 19th goal and a 2-0 lead at 1:42 of the second.
Moore capitalized on a Florida turnover at 2:53, putting Toronto on the board with his sixth goal off a loose puck that Luongo could not find.
Hyman tied it at 2 with his 12th marker off a fancy drop-pass at 12:34 by William Nylander, who leaned past Keith Yandle on his way through the slot to set up the goal.
With the game knotted at 2 through two spirited periods of play, neither team scored in the final period, but McElhinney stopped McCann on a late power play.
Luongo also stopped Nazem Kadri in the last seconds, forcing overtime.
--Field Level Media
Toronto | Florida | |
Zach Hyman 1 | Points | Jonathan Huberdeau 2 |
Zach Hyman 1 | Goals | Jonathan Huberdeau 1 |
Kasperi Kapanen 1 | Assists | Vincent Trocheck 2 |
N/A | Power Play Goals | Aleksander Barkov 1 |
N/A | Short Handed Goals | N/A |
Curtis McElhinney .903 | Save Percentage | Roberto Luongo .949 |
Curtis McElhinney 28 | Saves | Roberto Luongo 37 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
Toronto | 39 | 2 | 0-2 | 3-4 | 8 | 32 |
Florida | 31 | 3 | 1-4 | 2-2 | 4 | 29 |