Lee Tomlin salvaged a point for Cardiff and prevented Sheffield Wednesday moving into the Championship’s automatic promotion places on Friday.
The Bluebirds substitute curled home a stunning free-kick as a dominant Owls side left Cardiff with just a single point following the 1-1 draw.
Harris looked to have come back to haunt Cardiff when he created Julian Borner’s first-half goal.
The ball may have been heading for the back of the net, but as Neil Etheridge dived to his left, Borner stuck out a leg and diverted the shot away from the Cardiff goalkeeper and into the back of the net.
Cardiff survived until the interval but were on the back foot again after the restart.
Danny Ward had Cardiff’s first shot on target after 70 minutes before Josh Murphy’s deflected cross looped over the head of Cameron Dawson and flashed just past the post.
But the equaliser finally came after Tomlin dusted himself off after he was tripped by Massimo Luongo and sent a curling effort into the corner from 25 yards out to earn a point.
“I am disappointed we conceded the way we did,” Cardiff manager Neil Warnock told the BBC.
“We had quite a lot of crosses going astray,” he added. “Some of the balls into the box were poor tonight but we kept going and I thought we could have won it in the end.”