Montreal reached 82 points for the season, two in front of Philadelphia for the sixth position in the Eastern Conference. The Canadiens are just one point behind fifth-place Ottawa. Florida is seven points out of a playoff position.
Benoit Pouliot and Brian Gionta scored late in the first period and Montreal protected its 2-0 lead until Radek Dvorak tipped in a shot with 3:36 remaining in regulation to bring the Panthers within one.
Tomas Plekanec and Gionta then scored into the empty net during the final 1:24 to secure the victory.
Tomas Vokoun stopped 29 shots for Florida, loser of four of its last six.
Florida winger David Booth had to be helped from the ice during the second period after being hit in the head by a shoulder check from Jaroslav Spacek. Booth, who sat out 45 games this season due to a concussion, was taken to a hospital for observation.
No penalty was called on the play.