Jesse Curtis Morton, who went by the name Younus Abdullah Muhammed, was convicted of being a co-conspirator in Zachary Chesser's death threats against the two television creators, The Hollywood Reporter reported Friday.
The two were offended by an episode of "South Park" featuring the prophet Mohammed dressed as a bear.
The FBI said Morton helped Chesser on Web site postings by urging followers to pay Stone and Parker a visit and posting details of where they live.
"I justified atrocities by Muslims simply because they were carried out by the weak against the powerful," Morton said in a Virginia court before sentencing Friday.
A judge sentenced Chesser to 25 years in prison for his plot to kill the television duo, THR reported.