Eric Holder, 32, admitted during his trial to have killed Nipsey Hussle, rising star of American rap.
But he claimed to have acted "under the influence of passion", without having planned his gesture.
A version to which the jurors did not subscribe during his trial.
Last July, they found him guilty of murder and thus considered that it was a premeditated act.
On Wednesday, the judge responsible for setting Mr Holder's sentence sentenced him to a minimum sentence of 25 years for the murder, with an additional 25 years due to the use of a firearm.
He also received an additional 10 years for shooting and wounding two other men who were nearby.
The death of Nipsey Hussle in March 2019, at the age of 33, had deeply moved the United States.
After the drama, many stars, including Stevie Wonder and Snoop Dogg, had paid tribute to this highly esteemed rapper in the world of hip-hop.
Tens of thousands of people attended the ceremony held in his memory in Los Angeles, where a message from former US President Barack Obama was read.
Despite setting up his clothing store in the South Los Angeles neighborhood where he grew up, Nipsey Hussle remained tied to the gang world in which he grew up.
His murderer Eric Holder was a member of the "Rollin 60s Crips", an organization to which the rapper had also belonged.
Before dying, the artist had confronted his murderer by telling him of rumors that accused him of being a "libra".
During the trial, the prosecutor had estimated that the assassin had had "all the time to premeditate" his gesture.
Nipsey Hussle, born Ermias Asghedom into a family of Eritrean descent, was posthumously honored with two Grammy Awards in 2020, for his tracks "Racks in the Middle" and "Higher".
Last August, he was also awarded a posthumous star on Hollywood Boulevard.
© 2023 AFP