With a judge seeking to strike a balance between mercy and retribution, Oscar Pistorius, the South African track star, was sentenced Tuesday to five years in prison for killing his girlfriend, Reeva Steenkamp.
The athlete’s defense team said the law under which he was punished calls for him to serve only one-sixth of the prison term — 10 months — before he can be placed on house arrest. He was also given a suspended three-year term on separate firearms charges.
But some South African legal experts said the conversion of prison time to house arrest was not automatic and required negotiations with the correctional authorities. After serving half the sentence, Mr. Pistorius can also apply for parole.
Ms. Steenkamp’s family said it was “satisfied” with the ruling, although the National Prosecuting Authority said it had not yet decided whether to appeal.
“I’m just glad it’s over,” June Steenkamp, the victim’s mother, told reporters outside the courtroom.
Mr. Pistorius’s family said it was not planning to appeal. “We accept the judgment,” Arnold Pistorius, the athlete’s uncle, said in a statement, appealing to the news media to “let us move forward” and “give us some degree of dignity and privacy as we do so.”
“Oscar will embrace this opportunity to pay back to society,” the uncle said.
After a trial that opened in March and that was initially set to run three weeks, Mr. Pistorius seemed impassive as Judge Thokozile Matilda Masipa ordered him to rise to hear his sentence.
Just before he descended the courtroom steps to the holding cells at the North Gauteng High Court in Pretoria, the South African capital, he clasped the hands of relatives but showed little emotion. Earlier in the trial, there were times when he wailed, wept and vomited.
The often-delayed hearings have been broadcast around the world, captivating people in Mr. Pistorius’s own country and abroad. Every word has been broadcast — some of it restricted to audio coverage at the request of witnesses — and journalists have chronicled the trial’s every twist and turn in a barrage of Twitter feeds, dispatches, and televised interviews and commentary.
Virtually since the moment of the shooting, Mr. Pistorius has been free on bail, living in his uncle’s luxurious mansion. But for now, Martin Hood, a South African lawyer, told Sky News, Mr. Pistorius is a sentenced prisoner and will spend the night in a cell at Pretoria’s main prison.
“It’s going to be a cold, harsh reality for him tonight,” Mr. Hood said.
Live television images showed Mr. Pistorius being driven away from the courtroom in an armored police van. Blue-uniformed officers sat with him, while others, in bulletproof vests, were hanging from the rear.
In September, Judge Masipa found Mr. Pistorius, 27, guilty of culpable homicide but she acquitted him on more serious murder charges.
The prosecution had sought a 10-year jail term, while the defense had requested that he be placed under house arrest for three years and perform community service. Judge Masipa had wide discretion on possible sentences ranging from a fine to 15 years in prison.
The disabled athlete has admitted killing Ms. Steenkamp, 29, on Feb. 14, 2013, but he said he did so by mistake, firing four rounds from a handgun through a locked toilet cubicle door in the belief that an intruder had entered his home.
Judge Masipa spent 65 minutes summing up her decision before telling the athlete, “Mr. Pistorius, please rise.”
Quoting at length from legal precedents, Judge Masipa said her sentence was “about achieving the right balance — proportionality.”