The rap mogul, whose label once listed Dr Dre, Tupac Shakur and Snoop Dogg, pleaded no contest to voluntary manslaughter in exchange for the prison term.
He had been charged with murder, attempted murder and hit-and-run after fleeing the scene following a fight outside a burger stand in the Compton area of LA in 2015.
One man was hit by Knight’s car and another man, Terry Carter, was run over. Mr Carter died from his injuries.
Knight, wearing an orange jail jumpsuit, entered the plea at Los Angeles Superior Court ahead of his scheduled murder trial.
The former music producer will be sentenced in October when he will be handed the 28-year sentence.
As part of the agreement the murder charges against him will be dismissed by prosecutors, along with the separate criminal cases charging him with robbery and making criminal threats.