Tomas Vokoun made 20 saves and held firm in the third period with New York looking for the equalizer while both Karlis Skrastins and Jay Bouwmeester came up with first-period goals as the Panthers have won four of their last five.
Joshua Bailey and Trent Hunter scored for the Islanders, who were looking to cash in on a fifth consecutive victory.
Despite winning a season-high four straight games, the Islanders are still last in the NHL with just 37 points on the season. New York came into Thursday's clash with more victories in its last four games than it did in its previous 22 outings (2-17-3).
Joey MacDonald got the call in net for New York, allowing three goals on 29 shots in his first action since being activated from injured reserve Tuesday.
Florida took a 2-0 lead after 20 minutes, beating the rusty MacDonald with a pair of slap shots. Bouwmeester got one through traffic from the right point 5:41 into the game and Skrastins went top shelf from between the circles at 16:53.
Vokoun only had to face six shots in the first and stopped them all but despite the Panthers dominating the first half of the game, New York cut its deficit in half at 8:22 of the second, capitalizing on a power play. Chris Campoli and Bailey played catch on the right side of the net before Bailey uncorked a one-timer that slipped by on the short side.
A terrific effort from Zednik allowed Florida some breathing room a short time later as he raced up the right boards, leapt over a sliding defender while cutting toward the net and got it past MacDonald moving across the goal mouth.
A heads-up play by Hunter, though, got one back for the Isles as he secured a loose puck off an offensive zone power-play draw and scored on the backhand with 5:19 to go in the second.
Vokoun wasn't seriously tested in the third until MacDonald went to the bench with 1:22 on the clock but his seven saves in the frame were enough for the win.