Chumlong Lemtongthai, said by officials to be a "leading figure" in international rhino poaching, pleaded guilty to hiring prostitutes to take part in fake hunts during which rhino horns were harvested for smuggling, the BBC reported.
A demand for rhino horn is driven by its use in traditional medicine in Asia, especially in Vietnam where many believe ground rhino horn can cure cancer despite a lack of any supporting scientific evidence.
Horns are also smuggled to the Middle East and used to make handles for ornamental daggers, wildlife campaigners said.
Lemtongthai had been arrested and charged after a yearlong investigation by South African authorities.
In imposing the sentence, the court ruled Lemtongthai had shown no remorse for his crimes.
"The guilty plea does not necessarily imply anything more than that the accused is realistic," Magistrate Prince Manyathi said.