"I felt like my team needed energy," he said, "so I was trying to score in a lot of different ways."
Al Horford finished with 11 points and 13 rebounds for the Hawks, who have won nine of 11 at home to improve to 22-6 at Philips Arena.
Atlanta, however, endured Jamal Crawford's worst shooting performance in 55 games. The valuable sixth man, whose 17.2 scoring average is the Hawks' second-best, missed all seven of his field-goal attempts, including four 3-pointers, and finished with one point.
Starting forward Marvin Williams, who has a 10.1 average, was 0 for 4 from the field, so Atlanta coach Mike Woodson gave Smith more responsibility.
"Fantastic game," Woodson said. "He was all over the place. He blocked some shots. He scored for us, made some free throws. He was solid from beginning to end, and we're going to need him the rest of the way."
Kevin Love had 19 points and 12 rebounds for Minnesota, stuck at five road wins -- tied with Sacramento for third-fewest in the league.
Atlanta, which won Monday night in Utah for the first time since 1993, took its biggest lead at 16 on Maurice Evans' three-point play late in the third.
"We did a good job getting back in the game," Timberwolves forward Al Jefferson said. "That's all good. We could be happy with that, but we had a chance to win the game. Unfortunately, we fell short. Turnovers killed us."
The Timberwolves had hoped to win on the road for the second time in two nights, and they closed within two when Damien Wilkins' three-point play made it 78-76 with 10:14 remaining.
But nearly 2 minutes later, Smith took Horford's tip rebound on the right side and converted a three-point play to make it 85-80.
"We couldn't find a way to score and we were getting good looks," Minnesota coach Kurt Rambis said. "I thought our defense was pretty good for most of the game. That's what really carried us, but as usual for us as a ball club, we were inconsistent. We were inconsistent with our effort, inconsistent with our defense, inconsistent with our offense."
Jefferson took little satisfaction in playing a competitive game against Atlanta after losing by 25 in Minneapolis on Dec. 22. The Timberwolves have dropped eight straight in the series.
"At the end of the day we still lost the game, so I can't be too excited about whether we lost to them by 20 or we lost to them by six," Jefferson said. "We still lost."
Smith credited the Hawks' fourth-quarter success with fighting harder for offensive rebounds and passing more accurately.
"We knew [Minnesota] would not stop playing," Smith said after combining with reserve center Zaza Pachulia for six offensive boards. "When it got to two points, we came together and held on."
The start of Atlanta's game Friday against Dallas has been moved from 8 p.m. to 7 p.m. to accommodate television. ... Smith's previous high this season was 24 in a Jan. 1 home loss to New York. ... Early in the second, Timberwolves G Wayne Ellington was called for a flagrant foul on Atlanta rookie G Jeff Teague. Teague hit the ensuing two free throws to give the Hawks a 25-21 lead. ... Horford took his usual rest early in the fourth, but he didn't leave the game late in third despite hitting the back of his head on the backboard and falling backward to the floor. He was fouling Hollins on the play.