Garcia was seven-under through 15 holes, two strokes ahead of Sydney man Gale, who leapt to second on the leaderboard with his ace on the par-three 11th before play was suspended after his 12th hole at Royal Queensland.
Playing on his first DP World Tour card after a strong domestic season, Gale won a BMW from the $2.5 million event's sponsor after hitting an eight iron off the tee on the 168-yard (154m) hole.
It thudded into the bank of a greenside bunker on the right and rolled in, prompting the mullet-haired 29-year-old to take off his trademark yellow bucket hat and pump his fists in celebration.
Gale was not the only player to record a hole-in-one on the day, with young New Zealander Kazuma Kobori grabbing one on the par-three 17th "party hole" early in the morning during his two-under 69.
"My round was getting off to a relatively slow start and then that helped me boost it a little bit," Kobori told Golf New Zealand.
Players were allowed preferred lies on Thursday due to the amount of rain the course has taken from recent storms.
A group of four had the early clubhouse lead after shooting four-under 67s, including New Zealand's Ryan Fox, China's Ding Wenyi and hometown golfer Anthony Quayle, who had Tiger Woods' former caddie Steve Williams carrying his bag.
Williams, who came out of retirement to team up with Quayle at the event, helped the 31-year-old through a bogey-free round.
The group on four-under were joined by Colombian Sebastian Munoz and local golfers Nathan Barbieri and Jye Pickin, all of whom will finish their rounds early on Friday.
The local drawcards started well, with former Masters champion Adam Scott and Min Woo Lee shooting three-under, while British Open winner Cam Smith carded a two-under 69 after starting from the 10th.
Smith, a three-times winner of the event, had two bogeys with his four birdies but was happy with his putting in his first outing since coming back to his home state Queensland.
"It's started to feel really good this week, just being back at home and being on some familiar greens is probably good timing," said the former world number two, now on the LIV tour.
"I feel like I've hit a few good putts in the last couple of tournaments ad not many have gone in so it was good to see a couple go in."
Australian defending champion Elvis Smylie also started with a 69 off the 10th tee, while LIV golfer Joaquin Niemann was one-under through 15 holes.
The first round resumes at 6am local time on Friday, with the second to tee off following a 90-minute delay at 7:30a.m.