The huge animal, weighing in at 800lb (360kg) and measuring 15ft (4.5m), was shot by Lee Lightsey after he found it in his ponds surrounded by mutilated cattle.
It was the biggest animal he had shot in 18 years, the BBC reported, and he needed a tractor just to move it.
This picture shows his son Mason alongside the reptile hung up by a chain around its neck.
Mr Lightsey, a professional hunter, told the BBC: “Although this animal is huge I was not that surprised it existed.
“We have come across lots over the last 20 years that have been only a little smaller.
“But what really drew our attention to this animal was the fact that it seems to have been feasting on the cattle on my farm, because mutilated body parts were found in the water.
“It was a monster which needed to be removed.”
He has been commercially hunting alligators since 1988 and owns a company that arranges hunts for other enthusiasts.
Mr Lightsey stresses that all animals are killed “with the minimum of suffering”.
He charges $10,000 (£7,070) to hunt and kill an alligator more than 13ft long at his site in Florida.
His website shows a group of hunters proudly posing alongside a pack of dead alligators on the floor in front of them.