Al Jefferson led Utah with 26 points and 11 rebounds, while Derrick Favors had 17 points and 15 rebounds. It wasn't enough to prevent the Jazz (31-27) from losing their second straight home game and third straight contest overall.
Atlanta (33-23) took control when the Jazz opened the second half by missing their first eight shots. The Hawks went on a 10-2 run and took a 66-50 lead on a pair of free throws by Horford.
The Hawks appeared to be on the verge of securing a blowout road victory when they extended their lead to 80-60 on a pair of free throws from Zaza Pachulia with 1:24 remaining in the quarter. But the Jazz finally came to life on offense toward the end of the third quarter, going on an 11-2 run, culminating in a three-point play by Favors to cut the Hawks' lead to 82-71.
DeMarre Carroll kept the Jazz within striking distance late into the fourth quarter. Carroll twice helped Utah cut the lead to eight - first on a 3-pointer and then on a steal that he fed to Favors for a dunk that trimmed Atlanta's lead to 92-84.
The Hawks held the Jazz in check down the stretch, however. Horford made a pair of baskets to put Atlanta back up by 12. Then Smith hammered home a dunk after Favors hit a pair of free throws to cut it to 96-89 in the final minute.
The first quarter played out with Smith and Jefferson trading baskets. Smith made a hook shot to spark a 10-3 run and capped it with a dunk that gave Atlanta an early 18-11 lead. Jefferson helped rally the Jazz rally by making four straight baskets. The final one, a double-pump short jumper, left the Hawks clinging to a 27-25 lead with 20.5 seconds left in the opening quarter.
Jefferson tallied 11 points in the quarter, while Smith finished with 10.
Atlanta built the lead back up early in the second quarter, extended the lead to 39-30 on hot shooting from Horford, who made three baskets over a 3-minute span. Utah answered with a 9-0 run - capped by a driving layup from Alec Burks - to tie it at 39.
Horford and Jeff Teague combined to score 11 points in the final 2:30 of the first half to help Atlanta take a 56-48 lead going into the locker room. Teague started the onslaught with a 3-pointer and capped it with four free throws in the final 29 seconds.