Smith held off John Hunter Nemechek on a restart with eight of 134 laps remaining and then took the checkered flag 1.653 seconds ahead of Ty Majeski to win at Kansas Speedway.
Smith, 22, now has three wins this season – one each on a superspeedway, road course and now intermediate track. He led 108 laps in what was also the sixth victory of his career.
“It was just an unbelievable truck,” Smith said. “We struggled there in the first stage. I felt like I made mistakes last week with adjusting too much in the heat of the day and it wasn’t right in the night.
“This was our Vegas truck. I feel like this would have been an image of Vegas – what we did tonight – if I didn’t get damage early in the race there.
“That late-race restart scared me a little. It’s a good thing we didn’t have another one there because I was stuck in fourth (gear). So, sorry for the no burnout!”
Grant Enfinger ended up third, Chandler Smith fourth and Christian Eckes rounded out the top-five.
Completing the top-10 were Nemechek, Matt DiBenedetto, Derek Kraus, Matt Crafton and Ben Rhodes.
Stage 3
Following the break between Stages 2 and 3, all lead-lap trucks pit with Rhodes first off pit road. Jack Wood had to start from the rear of the field for running over the choose box.
When the race resumed on Lap 68, Rhodes was followed by Zane Smith, Corey Heim, Majeski and Tyler Ankrum.
Zane Smith quickly powered back into the lead on the restart.
With 50 laps remaining, Zane Smith had opened up a 3.8-second lead over Heim as Nemechek ran third.
Kris Wright hit the wall in Turn 2 on Lap 91 to bring out a caution. The lead-lap trucks all pit with Heim the first off pit road. Carson Hocevar had to restart from the rear for having an uncontrolled tire during his stop.
When the race returned to green on Lap 96, Heim led the way, followed by Zane Smith, Rhodes, Nemechek and Eckes.
Zane Smith again grabbed the lead on the restart as Nemechek moved to second and Eckes to third.
Heim was forced to pit under green on Lap 108 after hitting the wall while running seventh and had a tire go down.
With 20 laps to go, Zane Smith’s lead over Nemechek had expanded to 4.1 seconds as Majeski ran third.
On Lap 122, Dean Thompson spun down the backstretch to bring out just the fourth caution of the race.
The lead-lap trucks remained on the track and when the race returned to green on Lap 127, Zane Smith was followed by Nemechek, Majeski, Chandler Smith and Kraus.
With six laps to go, Majeski moved into the second position as Enfinger took over third.
Stage 2
Zane Smith cruised to the Stage 2 win over Heim by more than 2 seconds.
Nemechek was third, Majeski fourth and Rhodes rounded out the top-five.
Following the break between Stages 1 and 2, the lead-lap trucks all pit with Heim the first off pit road. Before pit road opened, Chandler Smith was forced to pit when his truck appeared to run out of fuel.
On the restart on Lap 37, Heim led the way followed by Nemechek and Zane Smith.
Zane Smith got back around Heim on Lap 38 to reclaim the lead in the race.
With 15 laps to go in the stage, Zane Smith’s lead over Heim had built to 1.4 seconds as Nemechek ran third.
Stage 1
Heim passed Zane Smith with eight laps to go and held on for the Stage 1 win, the first of his career.
Majeski ended up taking second, Zane Smith third, Nemechek fourth and Kraus rounded out the top-five.
Nemechek started on the pole and led the first three laps until Zane Smith went to his inside and came away with the lead on Lap 4.
With 15 laps remaining in the stage, Zane Smith maintained about a 1-second lead over Heim as Majeski ran third.
Heim finally ran down Zane Smith and passed him for the lead on Lap 22.
DiBenedetto and Tate Fogleman (unapproved adjustments) and Stewart Friesen (driver change) had to start the race from the rear of the field.