The 29-year-old, identified only as John Doe, had never told anyone about the abuse he claims he suffered until Sandusky was charged this month with abusing other boys. His lawyer said he filed a complaint with law enforcement on Tuesday. He became the first plaintiff to file suit in the Penn State child sex abuse scandal a day later.
Sandusky has acknowledged that he showered with boys but denied molesting them. His lawyer did not immediately return a message about the lawsuit.
The lawsuit claims Sandusky abused the boy from 1992, when the boy was 10, until 1996 in encounters at the coach's State College home, in a Penn State locker room and on trips, including to a bowl game. The account echoes a grand jury's description of trips, gifts and attention lavished on other boys.
"I am hurting and have been for a long time because of what happened, but feel now even more tormented that I have learned of so many other kids were abused after me," the plaintiff said in a handwritten statement his lawyer read aloud at a news conference.
The lawsuit seeks tens of thousands of dollars and names Sandusky, the university and Sandusky's The Second Mile charity as defendants. The man says he knew the coach through the charity, which Sandusky founded in 1977, ostensibly to help disadvantaged children in central Pennsylvania.
The man was not referenced in the grand jury report that charges Sandusky with abusing eight boys over a 15-year period.
His lawyer, Jeff Anderson, said he believes Sandusky was a predator who could not control his sexual impulses toward children. He harshly criticized officials at Penn State and The Second Mile who failed to report their suspicions and put a stop to any abuse.
"We need to address the institutional recklessness and failures," said Anderson, who specializes in clergy sex abuse lawsuits. "Was it because of power, money, fear, loyalty, lack of education?"
The university said it had not seen the complaint.
The charity said it would respond after reviewing the lawsuit but added: "The Second Mile will adhere to its legal responsibilities throughout this process. As always, our thoughts and prayers are with the victims and their families."
Anderson suggested that it ended four years later because Sandusky was not sexually interested in older teens.
The lawsuit was filed hours before students and high-ranking administrators participated in a town hall forum organized by students at Penn State's main campus in State College.
Penn State president Rod Erickson promised the university would raise the visibility of ethics "to a new level" following the scandal, which has rocked the campus.
"So hopefully everyone in the university understands ... we learn to do the right thing the first time, every time," Erickson said in opening remarks before an audience of about 450 students and employees at an auditorium in the student union.
The forum was broadcast on the school's public television station.
Sandusky was charged on Nov. 5 with abusing eight boys, some on campus. A grand jury said the allegations were not immediately brought to the attention of authorities even though high-level people at Penn State apparently knew about at least one of them.
The scandal has resulted in the departures of school President Graham Spanier and longtime coach Joe Paterno. Athletic Director Tim Curley has been placed on administrative leave, and Vice President Gary Schultz, who was in charge of the university's police department, has stepped down.
Schultz and Curley are charged with lying to the grand jury and failure to report to police, and Sandusky is charged with child sex abuse. All maintain their innocence.
In the lawsuit, the plaintiff said Sandusky gave him gifts, travel and privileges after meeting him through his charity in 1992. The abuse began shortly afterward, the suit said.
Anderson described Penn State and the charity as entwined institutions, and he charged that both failed to ensure that children were safe when they took part in trips and activities. He declined to say which bowl game the boy attended.
Sandusky took one boy he molested to the Alamo Bowl in Texas in 1999 and threatened to send him home when he resisted his advances, the grand jury said.
The bowl proved to be Sandusky's last game as Penn State's defensive coordinator. Once Paterno's heir apparent, Sandusky left after Paterno told him he would not get the head coaching job.
John Doe's lawsuit seeks a minimum of $400,000 in damages for sexual abuse, negligence, emotional distress and other claims. The accuser long thought he was the only victim and was mired in guilt and self-loathing, the lawyer said.
"Now that I have done something about it, I am feeling better and going to get help and work with the police," the accuser wrote in his statement.
Anderson declined to specify what sexual acts his client says took place, but he called them "severe." Nor would he say which police agency his client contacted Tuesday.
Police in Philadelphia and State College said they were not aware of such a complaint. The attorney general's office, which led the grand jury investigation, and state police said they could not disclose if a report was filed.
A university spokeswoman said police have received two complaints since Sandusky's arrest, the most recent from a prison inmate in Oklahoma, and both have been turned over to the attorney general's office. Anderson said his client John Doe is not that Oklahoma inmate.
By Anderson's count, the grand jury report lists 17 adults made aware of complaints or suspicions about the coach over the years, including those who knew of a 1998 complaint that Sandusky had showered with a Second Mile boy. Police pursued that mother's complaint and compiled more than 100 pages of investigatory notes, but no charges were filed.
Had John Doe known about that, he might have come forward to a parent or counselor years ago, Anderson said.
"Why were so many people, for so long, making choices that protected the institutions and not the children?" Anderson asked. "It's not just about Penn State, it's about all of us."
AP writer Genaro C. Armas contributed to this report from State College.