A Putnam County judge told Fay on Monday that he won't be eligible for parole until he's 78- years-old.
Fay pleaded guilty in October to two counts of aggravated murder in the shootings of 14-year-old Blaine Romes and his 17-year-old brother, Blake Romes.
Fay shot 14-year-old Blaine Romes in the head May 9 while he was sleeping on a couch and then shot Blake Romes, 17, in his bedroom, after they had gotten into an argument about whether Fay's older brother should move back into the mobile home, prosecutors said.
He shot them with a gun he got from a storage unit, said Todd Schroeder, an assistant county prosecutor. Both mothers were at work.
Fay had only moved into the trailer in rural northwest Ohio just a few weeks before the shootings.
He and the brothers were named in an Amber Alert in May after the Romes' mother discovered a gun and blood inside a trailer home where they lived.
Authorities at first believed that all three teens had been kidnapped after finding a bloody trail throughout the mobile home to the back door and tire tracks leading away from the trailer.
But only the Romes brothers were found dead.
Blaine was supposed to join his classmates on an eighth-grade class trip to Washington the morning he disappeared. His mother told a 911 dispatcher she left work because he was not answering his phone that morning.
Police found Fay later that afternoon at a gas station in Columbus, about 120 miles southeast of the trailer park in Ottawa.
He told officers that the Romes brothers were dead and pointed authorities to their bodies, the Putnam County Sheriff's Office said.