Bryan travelled from Salt Lake City, Utah, to the Ballogie Estate in Aboyne, Aberdeenshire, to take on the historic Dinnie Stones.
The 36-year-old managed to lift the huge boulders - weighing 733lbs (332kg) - and keep them off the ground for 33.9 seconds, beating the record of 31 seconds.
Mr Hunsaker is a 6ft 8in tall, 22-stone amateur weightlifter.
He travelled to Scotland to take on the challenge, and was watched by his family as he lifted the granite boulders while dressed in a kilt.
The former American footballe broke the 31-second record set only three weeks ago by current UK strongman Mark Felix.
He told STV News: “We had the trip planned before I knew about doing the stones.
“A lot of people have tried to lift the stones and a lot have failed. The UK strongman set the record three weeks ago and I’ve beaten that, which was something special in itself.
“I grew up in the UK so I’ve been to Scotland a few times. My family has ties to the MacDonald and MacGregor clans, going back 140 or 150 years.”
When asked if he thought his ancestors would be proud of his achievement, he said: “I hope so.”
The stones weigh 733lbs, one being 318lb 8oz and the other 414lb 8oz, and were originally carried by Donald Dinnie across the width of the Potarch bridge and back.
Malcolm Nicol, estate managing partner, said: “We have had interest in the Dinnie Stones from all over the world and it was a privilege to watch Bryan in front of his wife and family achieve his ambition to lift the stones.
“He travelled a long way from Salt Lake City in Utah to make the attempt and it is a fantastic achievement that not only was he successful in lifting the stones, but that he managed to hold the stones for an impressive 33.9 secs.
“We look forward to welcoming Bryan and his family back to Ballogie, he has expressed an interest in returning in August when we are planning an event at Potarch to emulate Donald Dinnie’s achievements in 1860.”