Sandusky and his wife, Dottie, were present for the reading of the verdict, MSNBC reported.
Earlier, Judge John Cleland dismissed three of the 51 counts against the 68-year-old.
Sandusky's case gripped the nation and led to the dismissal of a legendary coach and one of America's highest-paid university presidents, while his trial included gripping and at times graphic testimony from his victims, CNN reported.
The sequestered panel did not know about allegations from Sandusky's adopted son Matt Sandusky, who said on Thursday that his father abused him and said he had been willing to testify for the prosecution.
Matt Sandusky made the statement through his lawyers Andrew Shubin and Justine Andronici as the jurors began deliberations.
The verdict came after 21 hours of deliberations, Reuters reported.
A cheer went up among spectators outside the courthouse as the verdict was announced.
He now faces life in prison at his sentencing, which is weeks away, The Associated Press reported.