Oscar Pistorius, a once inspirational figure who gained international fame as an Olympic sprinter for South Africa before he was convicted of murdering his girlfriend, will be released on parole, the authorities said on Friday.
A parole board granted Mr. Pistorius’s petition on the basis that he had served half of his 15-year sentence he received for killing his girlfriend, Reeva Steenkamp, at his home a decade ago, making him eligible for parole according to South African law.
The Department of Correctional Services said in a statement that Mr. Pistorius was a “first-time offender, with a positive support system” and therefore met the requirements for parole, after a hearing at the Atteridgeville Correctional Center outside South Africa’s administrative capital, Pretoria.
Before his downfall, Mr. Pistorius was celebrated in South Africa and around the world as an athlete who had overcome personal adversity as a double amputee and fought for the right to compete in the Olympics, earning the nickname the Blade Runner for the carbon-fiber prosthetic blades that he used to race.
Mr. Pistorius, 37, will be released on Jan. 5, the statement said.
In March, the board denied Mr. Pistorius’s parole based on a technicality: The authorities had miscalculated whether he had served the minimum required period of detention, the Department of Correctional Services said at the time.
The calculation was based on a misunderstanding of when Mr. Pistorius’ sentence for murder began. Mr. Pistorius was initially convicted of manslaughter, but prosecutors appealed, and his conviction was upgraded to murder.
An appeals court increased his sentence from six years to 15 years in prison, the minimum recommended by South African law for unpremeditated murder.
Mr. Pistorius’s lawyers asked South Africa’s Constitutional Court, the highest decision-making body in the country, to rule on the parole matter. In October, the court ruled that Mr. Pistorius had served the minimum term and ordered correctional services to hear his parole petition.
The legal uncertainty recalls the complexities of Mr. Pistorius’s trial and eventual conviction for the killing of his girlfriend, Ms. Steenkamp, who was 29 at the time. Mr. Pistorius shot Ms. Steenkamp, a model, through a locked bathroom door in the predawn hours of Feb. 14 in 2013.
He maintained that her death was an accident and that he had fired his gun in the belief that an intruder had entered his upscale home in a Pretoria security estate.
Prosecutors argued that Mr. Pistorius had killed Ms. Steenkamp on Valentine’s Day in a jealous rage after an argument. During the trial, they pointed to text messages in which Ms. Steenkamp said she was afraid of Mr. Pistorius’ temper as evidence of a volatile relationship between the couple.
As part of the parole-consideration process, the board heard from Ms. Steenkamp’s mother, June Steenkamp. During the March hearing, the Steenkamp family lobbied against Mr. Pistorius’s bid for freedom.
June Steenkamp did not attend the hearing, nor did she oppose parole for Mr. Pistorius, but she did question whether he had been rehabilitated. In a statement, she recalled evidence of Mr. Pistorius’s temper, including the text messages and testimonies from former partners.
“I do not know to what extent his bad behavior still exists or were evident during his time of incarceration,’’ she said in a statement, read by Rob Matthews, a family friend whose daughter was also murdered by a partner, “but I’m concerned for the safety of any woman should this not have been addressed in his rehabilitation process.”
Ms. Steenkamp’s father, Barry Steenkamp, died in September at 80. In media interviews before his death, Mr. Steenkamp maintained that Mr. Pistorius had deliberately shot his daughter.
Mr. Pistorius had been celebrated as an inspirational figure. He was born without a fibula in either of his legs, the bone that runs between the knee and ankle, beside the tibia. His legs were amputated before his first birthday, and before his second birthday, he was walking on prosthetics.
By age 17, Mr. Pistorius had won gold medals in the 2004 Summer Paralympics in Athens. Despite continued wins in the Paralympics games, Mr. Pistorius was determined to compete against able-bodied athletes.
The world athletic body, the I.A.A.F., rejected his bid to compete in the 2008 Beijing Olympics, but, after winning an appeal, he later qualified for and was allowed to compete in the London Games.
He ran the 400 meters at the 2012 Olympics in London, becoming the first double amputee to compete in the Olympic Games. The fact that he did not win any medals did little to diminish his global profile.
His success on the track also brought wealth and a degree of infamy: He earned more than $1 million in endorsements with major brands and made headlines for crashing his boat in 2008 and for his extravagant taste in pets (two African white tigers).
He also earned a spot on People Magazine’s sexiest athletes list, while he and Ms. Steenkamp regularly walked the red carpet in South Africa.