Knight is best known for launching the careers of stars including Dr Dre
Rap mogul Marion "Suge" Knight has pleaded guilty to beating up his girlfriend in a Las Vegas car park.
The 43-year-old former Death Row Records boss admitted battery as part of a plea deal that saw two drugs charges and a coercion charge dropped.
He was arrested in August for allegedly punching Melissa Isaac and pulling a knife on her. He has been fined $340 (£235) and must have counselling.
Earlier this week, Knight was involved in a fight in an Arizona hotel.
Police say that, after they broke up the argument in August, they found that Knight was carrying ecstasy and hydrocodone.
Ms Isaac was not stabbed but was treated in hospital for her injuries.
Meanwhile, on Monday Knight was treated in hospital for broken facial bones after a fight at the W Hotel in Scottsdale.
Police officers at the scene said Knight was punched twice in the face in the fight, which was broken up by taser stun guns.
Two men were arrested and charged with aggravated assault.
Knight has a history of legal problems including time in prison for drug offences and breaking parole.
He is best known for helping to launch the careers of Tupac Shakur, Dr Dre and Snoop Dogg.
In 2006, a judge ordered trustees to take over Death Row Records after Knight filed for bankruptcy.
The label was later sold at auction for $24m (£16.7m).