The 29-year-old tourist from Kansas died after being struck by lightning while hiking Mount Etna on Sunday, the Associated Press reported.
On Monday Italian firefighters told AP that the man was hiking in an area that had been closed due to risks posed by the volcano. He was rescued by helicopter but later died in hospital.
Mount Etna has been erupting for nearly two weeks, and tourists have been climbing Etna to witness the volcanic activity, which last week prompted local guides to express safety concerns.
Volcanic clouds have closed or limited air traffic to Catania's airport for the majority of recent days.