New South Wales 3 for 50 trail Queensland 153 (Labuschagne 69, Conway 5-17) by 103 runs
Smith, playing his first first-class game in Australia since January 2018, flashed at his fifth delivery and the edge was grabbed by Joe Burns at second slip. It had been 54 innings, and nearly three years, since Smith had last bagged a first-class duck.
It was the second of three wickets for Gannon - who two months ago was playing against Bermuda, Cayman Islands and Canada in the T20 World Cup Americas Regionals Finals having qualified for USA through his mother's side of the family - during an impressive six-over opening spell which brought Queensland back into the match at the Gabba after they had been bowled out for 153 with Harry Conway claiming 5 for 17.
"It was pretty weird, I didn't really know what was going on," Gannon said of Smith's scalp. "I was just trying to put the ball in the same spot every time then a couple of things happened which was nice. He's an absolute weapon off the pads so the plan was go a little bit wider and fuller, but it was a drag down that got him in the end.
"This is my tenth season with the Bulls so it's been a long road but I think missing out on pre-season, going to England and playing some league cricket, then the states, really refreshed me for this year. I've come back really enjoying my cricket and it's probably the most fun I've had playing for a long time. Hopefully that shows."
On playing for USA, he said: "It was really weird, being an Australian and singing a different national anthem, standing behind another flag. It was a bit of an uneasy feeling to be honest but it was a really good experience. We'll see if we get the chance to do it again."
By the close, New South Wales had steadied themselves somewhat to reach 3 for 50 with David Warner unbeaten on 27 having survived the around-the-wicket attack of the Queensland bowlers which didn't quite have the same impact as Stuart Broad in the Ashes.
Only Marnus Labuschagne stood out for the home side with 69 on a well-grassed surface that offered pace and carry but few demons. However, the New South Wales attack were relentless and for significant periods dried up the scoring almost completely although Mitchell Starc went wicketless during his 17 overs.
It wasn't a great day for the Test hopefuls at the top of the order. Burns and Matt Renshaw resisted for more than an hour before Burns missed a full toss from Sean Abbott then Usman Khawaja was pinned lbw on the back foot as Conway earned his first. Having played well to get through the first session, Renshaw was undone by late movement from Trent Copeland shortly after the break with Smith taking a sharp low catch at second slip.
Good bowling earned the early wickets but Sam Heazlett provided a big helping hand when he pulled a short ball from Moises Henriques to long leg to leave Queensland 5 for 95.
Labuschagne, meanwhile, showed great patience and excellent judgement, a boundary bringing up his half-century from 129 balls which was followed by a brief flurry of runs, which compared the day's general rate of scoring. He could feel a little unlucky to be given out lbw to Conway with the replays suggesting the ball was swinging down the leg side. His departure marked a rapid finish to the innings as the last five wickets fell for 13 runs.