All it took was Magic coach Stan Van Gundy challenging Howard to play smarter and harder.
"I came out in the second half and just trusted my teammates," Howard said. "They made some open shots and I tried to dominate the paint. It doesn't matter if we're down 20, we're going to continue to fight."
Howard had 22 points and 17 rebounds, Vince Carter added 21 points and the Magic beat Atlanta 93-76 on Thursday night.
The Hawks dropped to 11-4 in a failed bid to tie Phoenix for the NBA's best record. They also missed a chance to improve to 8-0 at home for the first time since 1993-94.
Orlando wiped away the disappointment of a one-point home loss to Miami on Wednesday night with its sixth win in seven games.
"I said to them at halftime, 'The question is, does anybody want to play?' " Van Gundy said. "I think we were pouting. We were tired. It's easy to make an excuse, but at the end of the day they're going to give you a W or an L. Nobody cares how long they've been rested or anything else. Nobody cares."
Atlanta, which has dropped two straight following a seven-game winning streak, blew a 14-point lead after Joe Johnson banked in a jumper to begin the third quarter.
The defending Eastern Conference champion Magic went on a 25-10 run that ended with Carter's three-point play and a 64-63 advantage with 2:09 left in the third.
"We were playing against one of the top teams in the East," Johnson said. "We showed no signs of urgency in the second half."
Johnson finished with 22 points for the Hawks, a half-game behind Orlando for the Eastern Conference and Southeast Division lead.
Atlanta's half-court offense fell into a deep funk after Marvin Williams hit an 18-footer to give the Hawks a 57-44 lead with 10:26 left in the third.
Over its next 34 possessions, Atlanta managed just six field goals.
"It was like we forgot how we got the lead," Hawks coach Mike Woodson said. "We played so differently in the second half, so we have to go break this tape down and figure out why that is."
Howard had 16 points, 10 rebounds and three blocked shots in the second half.
"When he's in attack mode, we're a different team," Carter said. "Our focus was better in the second half. We were limiting them to one shot. We took care of the boards and the ball."
Reserve guard Anthony Johnson, who averaged 1.6 points over his first 20 games this season, scored 17 points in 21 minutes. His 3-pointer with 6:58 remaining gave the Magic their first double-digit lead of the game at 79-69.
Howard's dunk with 2:25 left put Orlando ahead 87-73.
"The last couple of games I haven't been aggressive enough," Howard said. "Tonight I just kept asking for the ball, and we played inside-out, and it was successful for us."
Josh Smith was the Hawks' second-leading scorer with 13 points.
Mike Bibby started despite leaving the Hawks' last game, a loss in New Orleans on Saturday night, with a sprained left ankle. He finished with 10 points on 4 for 11 shooting. ... Atlanta wore red uniforms with "ATL" stitched on the front of the jerseys for the first time. ... The Hawks announced a crowd of 19,193 for their second sellout this season. ... Orlando has won four straight at Philips Arena.