Duane "Keffe D" Davis, 63, found guilty of first-degree murder in August, received the penalty during a hearing in a Las Vegas courtroom on Tuesday.
Until Davis' 2023 arrest, the killing of Shakur, shot dead in the passenger seat of an SUV driven by his record executive, Marion "Suge" Knight, had stood for nearly three decades as one of America's most notorious cold cases.
The murder, which silenced one of rap's most commercially successful and influential artists, heightened the image of violence permeating 1990s hip-hop culture while stoking the infamous East Coast-West Coast "gangsta" rap feud of the era.
Despite Davis' conviction, the question of who pulled the trigger in the fatal shooting of the 25-year-old rap star has never been conclusively decided.
Davis was tried and convicted for masterminding the murder to avenge the beating of his nephew by Shakur and members of the rapper's entourage inside the MGM Grand casino on the Las Vegas Strip on September 7, 1996.
Davis, who was sentenced to a life term in prison without the possibility of parole, has said he would appeal his conviction.
The clash at the casino stemmed from hostility between two Los Angeles-area street gangs — the South Side Compton Crips, of which Davis was the self-described leader, and Mob Piru, which was associated with Shakur, Knight, and their music label, Death Row Records.
Members of both groups were in Las Vegas to see a world heavyweight title boxing match that night between Mike Tyson and Bruce Seldon.
Within hours of the casino brawl, Davis ushered his nephew and two other associates into a white Cadillac and went looking for Shakur and Knight, determined to settle scores, according to an account Davis later gave police in an unrelated investigation and that prosecutors cited during his murder trial.
Davis said he passed a gun to the two men seated behind him in the Cadillac, one of whom opened fire through the window when they caught up with, and pulled alongside of, Knight and Shakur's vehicle in traffic.
Shakur was struck four times and died in a hospital six days later. Knight, who suffered a minor injury from a bullet fragment that grazed his head, is now serving a 28-year prison term on an unrelated voluntary manslaughter conviction.
Authorities said they long believed Davis was involved in Shakur's killing but lacked sufficient evidence to charge him.
That changed when he went public with his story in media appearances and a memoir that, along with tapes of his secret meetings with investigators, formed the bulk of the prosecution's murder case.
While Davis was never accused of actually firing the shots that killed Shakur - Nevada law allows someone to be charged with murder as a participant in the crime - prosecutors have never named a suspected gunman.
All three other men in the Cadillac with Davis that night have since died.
