The first ever American to win a gold medal in judo, Kayla Harrison, overcame spells of depression brought on by her coach abusing her sexually during her early teens.
She achieved a dramatic win over Britisher Gemma Gibbons.
The gold medal caps an extraordinary journey for Harrison, who in 2007 put her former coach behind bars for sexually abusing her as a teen.
"I was kind of reflecting back on my life and everything that it's taken to get here, and everything I've gone through, and everything that everyone in my family has sacrificed," The Daily Mail quoted Harrison, as saying.
Harrison said she was focused on the gold: "This is my purpose."
"It's not every four years. It's every day. I'm just so honored to be America's first old medalist, and so happy to realize my dream. I'm America's first gold medalist in judo - and always will be," she added.
Harrison suffered years of abuse at the hands of her former coach Daniel Doyle, who was convicted in 2007 and sentenced to 10 years in prison for the offence.
"I can't describe how I felt. I think I cried pretty much every night," Harrison said.
Harrison turned the tragedy to triumph when her mother sent her to Wakefield, Massachusetts to train with Jimmy Pedro Jr., who won Olympic bronze medals in 1996 and 2004, and his father, Big Jim.
Together, the Pedros helped rebuild her confidence and she got past bouts of suicidal thoughts, and, in spite of her lowest points, she dragged herself to training every day.
Pedro Jr. gave Harrison the same pep talk over and over again today before the match, and helped her resurrect her career.
Harrison acknowledges the help she got from the Pedroes, and said: "As melodramatic as it sounds, it's true. The Pedros saved my life, and they changed my life. I don't even want to think about what would have happened to me if I had stayed there."