Walker had three 3-pointers in the extra frame as the Hornets outscored New York 20-11 to win their fourth straight game.
Trey Burke had 42 points and Michael Beasley had 27 to lead the Knicks, who lost for the third time in four games to fall to 27-48 on the season.
New York jump-started its offense in the third quarter, outscoring the Hornets 33-25. Charlotte went into the fourth quarter up 87-82 and led 92-86 with 10:22 left, but the Knicks went on a 20-9 run to take a 106-101 lead with six minutes left. The Hornets responded with a 13-4 run to go up four, but New York scored seven straight to go up 117-114 with 40.6 seconds left. Walker hit a 3-pointer with 21.5 seconds left to send it to overtime.
Marvin Williams had 13 points and Jeremy Lamb and Willy Hernangomez each had 12 points off the bench for the Hornets, who shot 54.8 percent from the field and 39.3 percent from 3-point range.
Tim Hardaway Jr. had 17 points and Enes Kanter added 15 points and 13 rebounds for the Knicks.
Charlotte took a 62-49 lead into halftime as Walker had 11 points and Frank Kaminsky had 10 off the bench. The Hornets got good production from their reserves in the first half, as they had 30 of the team's 62 points. Charlotte gave itself the early lead with solid shooting, hitting 52 percent in the first half and 91 percent from the free-throw line.
Frank Ntilikina had all of his 12 points in the first half on 6-of-8 shooting. Beasley added 10 points for the Knicks, who shot 41 percent from the field in the first half.
The Hornets remain home for a Wednesday matchup with the Cleveland Cavaliers before heading to Washington on Saturday.
The Knicks conclude a three-game road trip at Philadelphia on Wednesday before returning to Madison Square Garden for a Saturday matchup with Detroit.
--Field Level Media
New York | Charlotte | |
Trey Burke 42 | Scoring | Kemba Walker 31 |
Trey Burke 12 | Assists | Kemba Walker 7 |
Enes Kanter 13 | Rebounds | Dwight Howard 13 |
Tim Hardaway Jr. 5 | Free Throws Made | Dwight Howard 5 |
Michael Beasley 1 | Steals | Michael Kidd-Gilchrist 2 |
Luke Kornet 1 | Blocks | Marvin Williams 2 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
New York | 128 | 51.4 | 9-30 | 11-11 | 25 | 41 | 1 | 6 | 11 |
Charlotte | 137 | 54.8 | 11-28 | 24-28 | 25 | 43 | 4 | 5 | 15 |