"Today I will add my voice to this growing chorus. Three decades ago, as a college sophomore, I was sexually assaulted," said Murphy, who has been married to Gov. Phil Murphy for more than two decades and has raised four children.
"I was thrown on my back, I had a man on top of me" she said of the moment of terror. "[He] pulled my shirt up, pulled my skirt up and I started screaming."
Murphy didn't just yell, either.
"I started screaming bloody murder," she said.
Her attacker, she said, tried to muzzle her screams with a crab apple.
She said when the assailant tried to stuff the fruit into her mouth, "I bit him as hard as I could," eliciting cheers from the crowd.
Her attacker relented and Murphy said she "got up and ran into a fraternity house," where members called the police.
Murphy said that "despite my efforts to convict this man for what he did to me my assailant did not face justice in my case."
The first lady said for years this story remained private.
"Until today, only a few have heard my story," she said. "Now you all know. I tell this today not for me, but really for all of you. Surely, among us is a woman who has been silent about her own story."
Murphy is the co-founder of the public policy initiative New Start New Jersey.
Murphy's husband Phil Murphy was sworn in as New Jersey's governor earlier this month.