Vaughn was convicted of killing his wife and three children in a courtroom adjoining the one where Peterson was tried. The two trials overlapped.
George Lenard, the Oswego man's attorney, argued his client did not receive a fair trial because of the antics of Peterson's lawyers outside the Will County Courthouse.
But Judge Daniel Rozak rejected the argument, saying the Peterson case only bolstered Lenard's credibility with jurors, The (Joliet) Herald-News reported.
Rozak sentenced Vaughn to four life terms without parole, saying he was "frustrated" he couldn't do more.
Before sentencing, Vaughn's mother-in-law, Susan Phillips, called him "a selfish coward."
Vaughn was convicted of the 2007 shooting deaths of his wife, Kimberly, and their three children as they sat in their car. He also wounded himself, telling police it was his wife who had done the shooting. Jurors took less than an hour to convict him in September.
Peterson, a former suburban Chicago police sergeant, was convicted of the first-degree murder of his third wife Kathleen Savio. Peterson's fourth wife, Stacy, remains missing.