Chad LaRose had two goals and two assists in his first career four-point game. He and Staal scored 3½ minutes apart in the second period to help the Hurricanes win their second straight.
Brian Gionta and Marc-Andre Bergeron scored for Montreal, which could have wrapped up a postseason berth with one point but instead lost its second straight.
Bergeron pulled the Canadiens to 3-2 with 16:57 left with a blast from the blue line 21 seconds after Staal's second goal. LaRose made it 4-2 by tapping in Staal's rebound with 2:38 left.
Staal polished off his club-record 10th career hat trick with an empty-netter with 1:15 left. He entered tied with Hall of Famer Ron Francis in the Hurricanes-Hartford Whalers' record book.
Jaroslav Halak, making his fourth straight start since Carey Price lost to Carolina on March 31, stopped 28 shots. Cam Ward made 15 of his 30 saves in the third period for the Hurricanes.
Because of injuries and a flood of trade-deadline deals, there were 10 Carolina players active for the home finale who didn't skate in the Oct. 2 opener. More roster tweaks could come during the offseason when left wing Ray Whitney becomes an unrestricted free agent.
They did have Staal and LaRose — and that was plenty.
They combined for seven points Tuesday night in a win at Tampa Bay, and then they outdid themselves in this one.
They got things started early in the second period when Staal found LaRose, who popped the puck off Halak's pads, and Staal swooped in with a backhand at 18:36. Then, they hooked up again a few minutes later to make it 2-0, with LaRose pushing a backhander past Halak as he was being dragged down with 15:09 left.
The Hurricanes' duo looked to have furthered their jump start in their candidacy for spots in next year's All-Star game, which was awarded to Raleigh earlier Thursday. In fact, some of the loudest cheers of the night came when a scoreboard video was shown featuring NHL commissioner Gary Bettman congratulating the "Caniacs" for helping land the All-Star game.
NOTES: The Hurricanes recalled defensemen Casey Borer and Tim Conboy from Albany of the AHL. Borer made his first NHL appearance since he broke a vertebra in his neck in the River Rats' bus crash in February 2009. ... Montreal D Jaroslav Spacek (flu) was back on the ice missing three games.