Spencer Stone apparently trains at Gracie Lisboa’s branch at the Terceira Island in the archipelago of the Azores, in Portugal.
According to the academy’s Facebook page, Stone trains with instructor Simão Reis.
Stone and two other American military tackled the 26-year-old Moroccan national to the ground after hearing him load up a gun in the toilet.
Stone’s father told CNN that his son put the attacker in a choke hold.
Stone was injured in the back of the neck and almost had one of his thumbs severed by the terrorist, who pulled a knife.
He went under surgery in Paris and his condition is considered stable.