A female passenger, also in her fifties, was injured and is being cared for at Växjö hospital.
“They got the elk on top of them,” said Robert Mattebo at Kronoberg police.
The accident occurred late on Sunday evening.
A witness called the emergency services shortly after 10pm after noticing the motorbike in a ditch near the Rävemåla roundabout.
On closer inspection the witness then found the injured couple, who were unconscious and buried under the now deceased elk.
The man underwent an emergency operation during the night but his life could not be saved, Kronoberg police confirm.
The woman’s injuries are described by the hospital as minor.