Johnson, a Philadelphia native who met Jackson while living in Massachusetts in 2005, was also sentenced to nine months to five years for possession of an instrument of crime and three months to two years for abuse of a corpse, to be served consecutively.
Johnson, who has fathered nine children residing in Philadelphia, declined to address the court.
His attorney, William Bowe, asked the judge to take into account that Johnson has only one prior criminal conviction, for reckless endangerment, several years ago.
Assistant District Attorney Jennifer Selber, however, noted that in Salem, Mass., Johnson racked up 10 police reports for domestic violence against a former girlfriend, who did not take the matters to court.
"It was a just result given the horrible facts of this case," Selber said outside the courtroom.
At trial, Selber told jurors that Johnson had arranged for a woman to come from Massachusetts to Philadelphia. In the days before her arrival, Johnson tortured Jackson in the couple's Clearfield Street apartment.
Jackson's remains were found March 31, but Selber said she likely died March 28.
Ten of the 12 jurors were granted permission to remain in the courtroom to watch the sentencing, which Sarmina said was the first time she had received such a request. Selber said the request also was a first for her.
"They obviously were invested enough in the outcome that they wanted to see it all the way through to the end," Selber said.