The 7-0 Smith, in his fourth NBA season, scored a career-best 26 points to go with 10 rebounds and three steals.
Minnesota closed within 85-83 with 4:51 to play on a pair of free throws by Nikola Pekovic, but the Hornets then went on their late surge. Smith's two free throws with 1:54 remaining gave New Orleans an eight-point cushion.
Chris Kaman had 21 points, 10 rebounds and four blocks for the Hornets, who have won two out of three.
Minnesota dropped its fifth straight despite 29 points and 12 rebounds from Kevin Love.