Mangum stabbed boyfriend Reginald Daye with a kitchen knife during an argument in April 2011. Daye died at the hospital 10 days later from complications related to the stabbing.
The jury got the case Thursday afternoon. It had to choose between first-degree murder, second-degree murder, voluntary manslaughter or not guilty. It found Mangum not guilty of theft charges related to the case.
At the sentencing hearing, Daye's family asked Judge Paul Ridgeway for the maximum sentence, saying he was loved and didn't deserve what happened to him.
Ridgeway immediately sentenced Mangum to serve a minimum of 14 years in prison.
During the trial, Mangum and her lawyers had tried to argue she was afraid for her life and stabbed Daye in self defense. In his closing argument, defense attorney Daniel Meier told the jury that before the stabbing, Daye had Mangum on the floor choking her.
"He was bigger than her. He was on top of her. He was choking her. [She gave him a] single stab wound to the flank," said Meier.
But in her closing argument, Assistant District Attorney Charlene Franks said Mangum deliberately attacked Daye and characterized her as a serial abuser with a history of physical violence towards boyfriends - including a domestic violence arrest involving another man in 2010.
"The defendant was the abuser, the defendant is guilty of first-degree murder," said Franks.
Mangum testified in her own defense Wednesday. She told jurors Daye was angry with her because she had "disrespected" him by flirting with another man.
She said Daye hit her and knocked her to the floor. She said he told her he was going to make it so other men wouldn't want her by threatening to put hot water on her face. She said he went to the kitchen and returned with a knife that he threw at her.
Mangum said she locked herself in the bathroom, but Daye kicked down the door and grabbed her by the hair, before pulling her into the bedroom.
"He straddled me, hit me, and then he started choking me," she said. "I couldn't breathe. My head hurt real bad."
Mangum said she was afraid.
"I was just trying to survive and I felt like Reginald was trying to kill me," said Mangum.
Mangum previously made national headlines in 2006 when she accused a group of Duke University lacrosse players of sexually assaulting her while she worked as a stripper at a party. The accusations were later found to be false and North Carolina Attorney General Roy Cooper dismissed all charges filed against the students.