A Tennessee woman who said she was a 16-year-old sex-trafficking victim when she killed a man in 2004 has been released from prison Wednesday after she was granted clemency, according to the Tennessee Department of Correction.

Kim Kardashian West, Rihanna and other celebrities had lobbied for Cyntoia Brown's release, and then Tennessee Gov. Bill Haslam agreed in January.

Brown, now 31, will remain on parole supervision for 10 years on the condition she does not violate any state or federal laws, holds a job and participates in regular counselling sessions, Haslam's commutation says.

In a statement released Monday, Brown said she wants to help other women and girls suffering abuse and exploitation.

"I thank governor and first lady Haslam for their vote of confidence in me, and with the Lord's help I will make them as well as the rest of my supporters proud," she wrote.

Her lawyers said she's requesting privacy and transition time before she makes herself available to the public.

Shot real estate agent in the head

Brown was convicted in 2006 of murdering Nashville real estate agent Johnny Allen, 43. Police said she shot Allen in the back of the head at close range with a gun she brought to rob him after he picked her up at a drive-in restaurant in Nashville to have sex with her.

The U.S. Supreme Court has ruled against life-without-parole sentences for juveniles. But the state of Tennessee argued successfully in lower courts that Brown's sentence was not in violation of federal law because she would be eligible for parole after serving at least 51 years.

Brown, a teenager when she was convicted of killing a real estate agent, says she was a victim of sex trafficking at the time. (Lacy Atkins/The Associated Press)

Haslam said that was too harsh a condition for a crime Brown admitted to committing as a teen, especially given the steps she has taken to rebuild her life. She earned her GED (certification she has high school-level skills) and completed studies with Lipscomb University as an inmate.

Brown met with prison counsellors to design a plan for her release, which will include time in a transition centre and continuing coursework with the Lipscomb University program, the state Department of Correction said in a news release.

Brown plans to have a book published in mid-October and a documentary about her is set to be released this year, the non-profit documentary film group Odyssey Impact and Daniel H. Birman Productions Inc. said in a news release earlier this year.

Brown ran away from her adoptive family in Nashville in 2004 and began living in a hotel with a man known as Cut Throat, who forced her to become a prostitute, and verbally, physically and sexually assaulted her, according to court documents.

Brown's lawyers contended she was a victim of sex trafficking who feared for her life and lacked the mental capacity to be culpable in the slaying because she was impaired by her mother's alcohol use while she was in the womb.