Bulger, 84, was defiant to the end, calling his trial on racketeering charges a sham and refusing to testify or provide information to probation officials preparing a sentencing report for the judge.
A jury convicted Bulger in August in a broad racketeering indictment that included murder, extortion, money-laundering and weapons charges. The jury convicted Bulger in 11 of the 19 killings he was charged with participating in but acquitted him of seven and could not reach a conclusion on an eighth.
Judge Denise Casper heard testimony Wednesday from a dozen relatives among the 19 slaying victims. They called him a terrorist, a punk and even Satan. Prosecutors called him a sociopath.
On Thursday, Casper told Bulger the depravity of his crimes is "almost unfathomable," calling them "heinous" and "all about money." Bulger looked directly at her, listening intently.
"The testimony of human suffering that you and your associates inflicted on others was at times agonizing to hear and painful to watch," Casper said.
She then sentenced him to two consecutive life sentences plus five years, as prosecutors had requested.
Bulger, the inspiration for Jack Nicholson's sinister character in the 2006 movie "The Departed," was seen for years as a Robin Hood figure who bought Thanksgiving turkeys for working-class South Boston residents and kept hard drugs out of the neighborhood. But that image was shattered when authorities started digging up bodies more than a decade ago.
Prosecutors at his two-month trial portrayed him as a cold-blooded, hands-on boss who killed anyone he saw as a threat, along with innocent people who happened to get in the way.
Corrupt Boston FBI agents protected Bulger for years while he worked simultaneously as a crime boss and an FBI informant who ratted out the rival New England Mafia and other crime groups.
Former Boston FBI agent John Connolly Jr. - Bulger's handler when he was an informant - was sentenced to 10 years in prison after being convicted of tipping him off ahead of an indictment. After receiving the tip in 1994, Bulger fled Boston and remained a fugitive for more than 16 years until he was captured in Santa Monica, Calif., in 2011.
Connolly was later convicted of second-degree murder in Florida for leaking information to Bulger that led to the slaying of a gambling executive.