Chris van Wyk, 42, was arrested in 2006 after he - and not the Vietnamese hunter or the professional hunter who should have accompanied him - shot the rhino.
Van Wyk was found guilty in July 2010.
His conviction related to a hunting trip on April 27 2006 at the Leshoka Thabang Game Lodge in Roedtan in Limpopo, in which Van Wyk and a Vietnamese client, Nguyen Tien Hoang, were involved.
Van Wyk organised the hunting trip through Tienie Bamberger, a professional hunter and the owner of Warthog Safaris in Ellisras, and was introduced to his Vietnamese client in Naboomspruit.
Bamberger received permission for the hunting trip from the owner of Leshoka Thabang, Johan van Zyl. Bamberger was not present on the day of the hunting trip and his wife, Ananya and his father accompanied Van Wyk and Nguyen.
When they found the rhino, the Vietnamese man walked away. Bamberger's wife, her father-in-law and Van Wyk shot four times at the rhino from a distance of between 50m and 100m.
Van Wyk didn't have a permit to hunt the rhino and was also not registered in Limpopo as a professional hunter.
On reading the verdict, Magistrate Gerhard Pretorius emphasised that Van Wyk during his trial in a police raid in the Free State was found with rhino horn and ivory and was also arrested in the Western Cape after being found with rhino horn. He was found guilty in both cases.
Pretorius said it pointed to Van Wyk's tendency to clash with the law in such incidents.
Pretorius said it was just a moneymaking racket. "This is a circus in which 23 people get on a vehicle and watch as animals are shot dead."
Pretorius warned Van Wyk that the "prison doors were coming closer and opening wider" should he continued his activities.
Outside court, Van Wyk said he thought the sentence was fair.