Mike Hodge, 67, suffered injuries to his neck and jaw during the attack in the Marakele Animal Sanctuary in Thabazimbi area, Limpopo province.
Footage shows Mr Hodge being pounced on by the big cat as he tries to leave through a gate, before he is dragged off towards some bushes.
Another man is heard shouting: “Somebody get a rifle, just in case” and a sobbing woman says: “Please, somebody help him.”
Gunshots are then heard.
Mr Hodge entered the lion’s enclosure over concerns about a smell in the compound that was bothering it, according to reports.
South African Police spokesman Lieutenant Colonel Moatshe Ngoepe told News24 officers were investigating the incident, which happened on Monday.
“The owner was immediately taken to hospital with serious injuries. He is currently recuperating,” he added.
The lion, called Shamba, was reportedly put down after the attack.
A spokeswoman for the Hodge family, Bernadette Maguire, reportedly said in a statement the incident happened as tourists were being shown around the sanctuary.
The statement also said Mr Hodge was “only too aware of the dangers of working with wildlife but they remain his passion” after the incident.
It said the family were “devastated” at the death of the lion, which they raised from a cub.
