SAN RAFAEL, Calif. — Alex Harrison waited a dozen years for one more chance to be believed.

The first time he testified, he was a guilt-ridden college tennis player who had alleged that his revered high school coach had abused him. But the criminal case ended in a mistrial, the coach was a free man, and Harrison — ostracized by his teammates, his friends’ parents and his insular hometown in Marin County, Calif. — descended into anxiety and self-doubt.

By the time Harrison swore to tell the truth last week, circumstances had changed. His former coach, Normandie Burgos, was in prison after being sentenced to 255 years to life for molesting two other tennis pupils. Harrison had become a prosecutor in Southern California, and gone public in The New York Times about his trauma. And now, Harrison was taking the stand in his own civil case against his former school district, accusing it of being negligent.

“I didn’t understand how to reconcile who he was with what he had done,” Harrison told jurors during testimony over two draining days, sometimes breaking down in tears. “At that time, as a kid, I hadn’t been a prosecutor. I hadn’t been an adult. I didn’t have life experience like I do now.”

It is hard to overstate how much has changed when it comes to reporting sexual abuse in youth sports since Harrison talked to the Mill Valley Police Department in 2006 to warn his community and protect other students, in vain.

The sexual abuse scandal involving Jerry Sandusky, a longtime assistant football coach at Penn State, had not yet come to light. Nor had the ones orchestrated by Lawrence G. Nassar, the former doctor at Michigan State and the U.S.A. Gymnastics team, or Richard H. Strauss, a doctor for the Ohio State wrestling team. The occasional story about a young athlete being molested in, say, swimming or figure skating, gained little traction.

Only in recent years have some states temporarily lifted statutes of limitations to allow adult survivors of childhood sexual abuse to sue abusers and institutions. The Child Victims Act in New York is one example. In California, a law that went into effect in January 2020 and expires at the end of 2022 has resulted in thousands of claims alleging sexual abuse by coaches, teachers, clergy and others.

And while numerous claims have been settled — including two related to Burgos — few have gone to trial. So it was all the more poignant, for Harrison, that his case against the Tamalpais Union High School District ended up in the same courthouse where he had been ridiculed as a young man, offering a bittersweet full-circle moment.

“I wanted to help victims of crime not be as traumatized by the criminal justice system as me,” Harrison testified. “And I thought that maybe somehow if, since I couldn’t get Mr. Burgos convicted, maybe if I got other sex offenders convicted, it would help me move on with my life.”

The civil trial unfolded at the Marin County Civic Center, a national landmark designed by Frank Lloyd Wright, where part of the 1997 sci-fi movie “Gattaca” was filmed. And though Burgos, 58, remains in prison after recently losing an appeal, his presence was inescapable inside the intimately circular courtroom, where the jury box, witness stand and lawyers’ tables were arranged in a crescent moon, so participants could always see one another.

One prospective juror was excused after saying that years ago, when he was a student and walking home from school, Burgos tried to lure him into his car. Stevie Gould, a former Burgos protégé whose secret recording of the disgraced coach admitting to having sex with a minor led to Burgos’s arrest, sat in the gallery twice to support Harrison.

But at the heart of the case was Harrison, now 36, who disclosed that he still has nightmares and panic attacks, and has seen numerous medical professionals for treatment.

As a Tamalpais High School student, Harrison said he feared reporting Burgos, who was also a popular gym teacher, because he had so much to lose. Yet when he went to the police, in college, he was mocked and scorned by a community that fiercely believed Burgos.

“I just felt like it was so wrong to be portrayed that way in a courtroom,” he said. “It just felt like a circus, in terms of all these people, all these people I thought were friends, once upon a time on the tennis team, the parents, my teachers, people who had given me recommendations for a school.”

Jurors this spring also heard from six contemporaries of Harrison’s — including five who were coming forward for the first time — with similar harrowing experiences.

One witness, a former football player identified only by his initials, A.G., said he had never told anyone about what happened until he read about Harrison’s lawsuit in the Marin Independent Journal two years ago. By then he was a young father, and said he was compelled to contact Harrison’s lawyers.

A.G. testified that he was alone in a locker room with Burgos, the door closed, when Burgos asked him to strip down to his boxers. Burgos then yanked the waistband of his boxers and used calipers to pinch his pubic area.

“I felt that even if there’s a small chance that the school system could be improved by hearing my story, just for the benefit of my kids, if nothing else, then I felt it was my responsibility to share this story,” he testified.

Questions of negligence and responsibility loomed large when Harrison’s lawyers called on a police officer and school officials, among others, as witnesses.

Two assistant principals from that time said they could not recall ever being briefed by the school’s former principal, Chris Holleran, about any concerns over Burgos or protocols to administer body fat tests, even though they were charged with supervising him.

“The only person at the high school ground level with a clue was Holleran — no one else,” said Bob Allard, one of Harrison’s lawyers. “That’s negligence.”

The use of physical tests, like fat tests, as pretexts to molest young athletes has come up in other cases. Just a few days before Harrison’s trial began, a former student-athlete at North Kingstown High School in Rhode Island, accusing a former basketball coach of widespread misconduct, sued former school administrators and athletic officials for failing to protect students and brushing off complaints.

“You don’t just normalize the behavior with the victim; you normalize the behavior with the community,” said Timothy J. Conlon, a lawyer for the Rhode Island plaintiff. “You create some facade or pretext that causes the behavior to be accepted even though it shouldn’t be.”

In Harrison’s trial in Marin County, lawyers for the school district said it had acted reasonably with the limited information that it had at the time.

“What we shouldn’t do is analyze the case with 20/20 hindsight,” said Marina B. Pitts, the district’s lead attorney. “What may seem obvious now was not obvious then.”

Pitts also contended that Burgos had gone rogue and sometimes acted surreptitiously.

“The harm was caused by Mr. Burgos,” Pitts said during her calm, almost clinical, closing arguments. “He’s the one who broke the rules.”

But Allard, using colorful slides, outlined the timeline of what happened, and what the district should have known. He urged jurors to place themselves in the shoes of a parent, or a community member who cared about its schools.

“We’re moving forward,” he said. “We’re setting standards. This is not how we want people treating sexual abuse victims.”

On Tuesday, the second day of deliberations in a trial that took just over two weeks, the jury of eight men and four women reached a verdict.

Yes, the district had been negligent.

Yes, that negligence was a significant factor in harming Harrison.

And for his suffering, both past and future, Harrison should be awarded $10 million in damages.

Harrison hunched over and sobbed, consoled by Allard and Mark Boskovich, his lawyers. After gathering himself, he thanked Superior Court Judge James T. Chou “for letting me be heard.”

A few of the jurors lingered.

“Can I give you a hug?” one suddenly asked Harrison.

Harrison, weeping, told her, “Thank you for caring and believing in me.”