Rick Nash had three assists, including a nice backhand pass that set up Zuccarello's game-winner after the Rangers squandered a two-goal lead in the third period. Dominic Moore added a goal and an assist for New York, and Cam Talbot made 29 saves in his fourth straight start for injured goalie Henrik Lundqvist.
Dan Boyle and Kevin Hayes also scored for the Rangers, who had lost two in a row.
Morgan Rielly scored twice, and Daniel Winnik and Stephane Robidas each had a goal for the Maple Leafs. James Reimer stopped 34 shots in his third consecutive start.
It was the 12th loss in 13 games for the Maple Leafs, who have three points during that span.
Interim coach Peter Horachek cut star Phil Kessel's ice time and demoted him to the fourth line. Kessel was on for four goals against and finished with his second-lowest ice time of the season.
Kessel played just 12:57, including some time in the third period with Trevor Smith and David Booth, after being at least partially responsible for Toronto falling behind. The Maple Leafs (23-28-4) mounted a comeback to tie the score, but Kessel was on again for Zuccarello's decisive goal.
Last week, Horachek took Kessel, Tyler Bozak and James van Riemsdyk out of their traditional white practice jerseys that denoted the first line and put them in red to take them out of their comfort zone.
At the end of two periods, Bozak had played the least of any Maple Leafs player, but by the midway point of the third Richard Panik was on the first line in Kessel's spot. Kessel got a couple of other chances with Toronto trying to tie it, but to no avail.
NOTES: Maple Leafs captain Dion Phaneuf missed his seventh straight game with a hand injury. Clarkson was a healthy scratch for the second straight game. ... Rielly's two-goal game was the first of his career.