Mark Scott-Crossley, 37, and one of his employees were, beating him, tying him up and throwing him over the fence at a lion reserve, where he was devoured.
Scott-Crossley's employee and co-defendant, Simon Mathebula, was sentenced to 15 years because the judge found had been coerced by his employer. The pair were convicted in April.
Chisale, 41, had been fired two months earlier for apparently running a personal errand during working hours. When he returned to collect some belongings, the two men attacked him.
Judge George Maluleke in the northern town of Phalaborwa said court guidelines say life sentences should be imposed when society needed to be protected from the possibility of a repeat offense or because the offense was so monstrous that it demanded harsh punishment.
"No crime fits this description more than the one before me and there is no doubt it would warrant this extreme punishment," the judge said.
Spectators in the courtroom whistled and cheered as Scott-Crossley was led out of the courtroom after the sentencing.
South Africa's Human Rights Commission said in a 2003 report that attacks on farm workers were common. Most are black or mixed race and their bosses are white.
According to testimony during the trial, Chisale was assaulted on Jan. 31, 2004 and tied to a stake. After being tied up and bleeding for six or seven hours, Chisale was taken to the Mokwalo White Lion Project and thrown over the fence, screaming as the animals tore at his body.
Witnesses testified that Scott-Crossley had a history of aggression and violence.
The judge said Scott-Crossley forced Mathebula to participate.
"More importantly, he disclosed to the police his complicity in the crime shortly after he was arrested," the judge said.
The trial of a third accused, Richard Mathebula, another former Scott-Crossley employee involved in the incident, was postponed until November because of illness. A fourth man originally accused, Robert Mnisi, was given immunity from prosecution when he agreed to testify for prosecutors.
Scott-Crossley, who was married by a magistrate Friday morning before his sentencing, was led from the courtroom along with his new wife. His attorney, Charl van Tonder said the verdict and the sentence would be appealed.
Mathebula's legal aid-appointed lawyer, Mduduzi Thabede, also said he intended to appeal.
The case highlighted the currents of violence that run through impoverished rural areas, as well as the harsh treatment meted out to farm laborers, who are usually black or mixed-race, by their bosses, who are usually white.