William Balfour, 31, was convicted on May 11 of first degree murder for the deaths of the singer's mother Darnell Donerson, her brother Jason Hudson, and nephew Julian King. He was also convicted of home invasion and residential burglary.
According to TMZ, the judge in the Chicago court told Balfour: "Your soul is as barren as dark space."
Jennifer was present in court to hear the sentencing.
Earlier today, Balfour requested a new trial, but the judge denied him the privilege.
Prosecutors claimed that Balfour committed the triple murder, which took place in October 2008, as a result of feelings of jealously towards his ex-girlfriend, Jennifer's sister Julia.
After finding out that Julia had received a gift from her new boyfriend, Balfour was said to have executed the triple killings.