The 29-year-old Blue Bulls prop pleaded guilty Friday to culpable homicide and drunk driving after days of plea-bargaining.
Roux initially was charged with murder for beating Sgt. Ntshimane Mogale to death on Aug. 27 after he was pulled over for drunk driving. Roux's lawyer has said he was acting in self defence.
Roux also was ordered to pay 750,000 rand ($110,000) to the family of Mogale.
The court and family accepted an apology from Roux. The judge handed down the sentence after checking that Mogale's wife was agreeable.
Roux won the 2010 Super14 with the Bulls.