Butler, who only played 6 minutes in the fourth, had a game-high 29 points on 8-for-14 shooting from the field and 12-for-16 shooting from the line.
Forward Mike Scott led the Hawks (2-2) with 15 points.
Pau Gasol had 11 points and seven rebounds for Chicago, and Joakim Noah had seven points and 13 rebounds. Derrick Rose had 10 points in 20 minutes.
Chicago (3-2) struggled to score for much of the game, managing no more than 17 points in any of the first three quarters before erupting for 38 points in the final quarter.
The Bulls also rallied from a 21-point deficit in the first half Monday night to beat Denver 110-90.
Chicago coach Tom Thibodeau put starters Butler, Noah and Gasol back in the game midway through the fourth and they led the rally against Atlanta reserves.
Butler tied the game at 82 with three free throws with 14.1 seconds left. Dennis Schroder (11 points) hit a driving layup with 1.5 seconds left to put the Hawks back on top and set the stage for Butler’s game winner.
