Brian White scored the tying goal in the 60th minute as the Whitecaps prevailed while playing in Vancouver for the first time since Sept. 16, 2020.
Diego Rossi scored on a penalty kick for Los Angeles FC (6-9-5, 23 points), who dropped their fourth straight game and saw their winless stretch reach seven (0-5-2).
LAFC star Carlos Vela departed in the 16th minute with an apparent leg injury.
Gauld's goal was his first in four games since joining Vancouver (5-7-8, 23 points).
The comeback victory gives the Whitecaps an eight-match unbeaten stretch (3-0-5).
The match marked the first time Vancouver played in front of home fans in 539 days. The Whitecaps did play three matches without fans in British Columbia last September.
The decisive tally was set up by Ryan Reynoso, who sent a cross toward the goal. Gauld was open and easily sent the ball past LAFC goalkeeper Tomas Romero into the right corner of the net.
Whitecaps goalkeeper Maxime Crepeau made six saves, while Romero had one.
LAFC held a 24-10 edge in shots and placed seven on target to Vancouver's three.
LAFC was awarded the penalty kick after Vancouver's Javain Brown was called for a foul in the penalty area.
Rossi approached for the kick two minutes into first-half stoppage time and Crepeau reacted by moving to his right. That left it easy for Rossi to kick it the other way into the right corner of the net for his sixth goal of the season.
Vancouver knotted the score in the 60th minute as White's close-range right-footed shot hit the crossbar and landed behind the line before bouncing back into the field of play. It was White's fourth goal of the campaign.
LAFC had two solid opportunities to move back ahead three minutes later.
Rossi's hard right-footed shot was stopped by Crepeau and the ball went to Brian Rodriguez, who delivered a right-footed blast that caromed off the goalpost.
LAFC dominated play in the first half and had a 14-4 edge in shots.
Rossi had opportunities in back-to-back minutes late in the half -- his right-footer in the 37th minute was wide and Crepeau saved his left-footed shot one minute later.