Aaron Fisher, 18, revealed his identity and spoke exclusively with ABC News. Fisher was the first victim to come forward to police about Sandusky, a former Penn State assistant football coach who was convicted earlier this year on 45 counts of child sex abuse.
In his interview, Fisher says Sandusky was sexually abusing him by the time he was 12 years old. He says Sandusky would often pull him out of school and have him over for sleepovers. Fisher also explained why he waited so long to come forward and the shocking reaction he received when he did.
"Here I am, beside my mom, crying, telling them and they don't believe me," he said in an interview with Chris Cuomo that airs on "20/20" Friday at 10 p.m. "I knew they wouldn't."
Fisher said he met the now 68-year-old Sandusky in the summer of 2005 at summer camp run by Sandusky's charity organization for disadvantaged children, The Second Mile. He said Sandusky immediately took a special interest in him and took him to sporting events. He said Sandusky, who had a great reputation in the community, was initially "like a giant stuffed teddy bear" and an "all-natural father figure." But that slowly changed.
"He'd put his hand on my leg while we were driving," Fisher said, adding that he knew it was weird.
Fisher said fear, shame and confusion stopped him from getting help and telling anyone about the abuse. It wasn't until he was 15 that he had the courage to tell his mother and his principal at Central Mountain High School about the abuse.
Fisher told ABC News that the principal didn't believe him, saying "Jerry has a heart of gold and that he wouldn't do those type of things."
"They tell me to go home and think about it," Fisher said.
But school officials did report Sandusky to Clinton County Children and Youth Services, which began an investigation. Sandusky was not arrested until November 2011 after more allegations against him surfaced.
Sandusky has been sentenced to 30 to 60 years in prison, which effectively means the 68-year-old will likely die in prison. His attorneys filed a motion Thursday, saying their client's trial wasn't fair and claiming there was never enough evidence to convict him.
They're asking the judge to toss the charges out or give Sandusky a new trial. The attorneys also claim the statute of limitations on some of the charges expired.
ABC News contributed to this report.