The 24-year-old from Perth, playing on a sponsor's invite, made the most of his opportunity as he added a stunning nine-under 63 to his first-round 69 to take a one-shot lead over Spaniard world No 13 Sergio Garcia, Ireland's Shane Lowry and Swede Peter Hanson, who were tied second at 11-under 133.
Garcia, making a comeback from a wrist injury, shot a five-under par 67, the same as Hanson, while Lowry, who won the Irish Open as an amateur last year, shot a round of seven-under par 65.
England's Chris Wood, Welshman Rhys Davies and German Martin Kaymer, champion here in 2008, were tied for the fifth place at 10-under 134.
The reigning European Tour Order of Merit winner, England's Lee Westwood (three-over 147) was the most notable casualty as the halfway cut was applied at two-under 142.
Kulacz, who fell in love with the game as a three-year-old when he was forced to stay awake at night after an asthma attack and watch Aussie legend Greg Norman play the Open Championship on television, was three-under at the turn with four birdies and a bogey.
But once he drained a 40-footer birdie putt on the 18th, there was no stopping him as he made just about every putt and chipped in as well.
On the back nine, he had seven birdies and one bogey before finishing with a par.
The Aussie, who won the Brunei Open on the Asian Tour in his rookie year and shot a superb round of 64 on the final day of the Qualifying School to secure his 2010 Tour card, said: "I got off to a really good start.
"I birdied 10th with a two putt and hit it to probably two feet on 12. So, the momentum was there straightaway.
"I got a really good break on 18 and holed it from 40 feet up the hill, and maybe a better break on the first where I chipped-in from over the back of the green.
"I just tried to get it on the green anywhere, and the putts just seemed to be going in. It was just one of those days where everything went my way and hopefully I can keep that going the next two days."
Garcia, who could not hit a single shot till last week after hurting his wrist during the third round of Dubai World Championship in November, was on song as he made six birdies in a round of 67.
Starting the round with a 50-feet birdie putt, the world No 13 hit the ball solid throughout the day, but said he still did not control his shots as well as he would like to.
"I am very pleased with this beginning, especially after the break and the little practice that I was able to do," said Garcia.
"So, it's good to see that I'm getting it around. I'm obviously not feeling in total control of my ball flight, but I feel like I more or less know how I'm hitting it and I'm scoring pretty well.
"Overall, it's been very positive and hopefully we can keep going on."
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