Kayla Harrison says she almost quit judo because of sexual abuse by a coach. Instead, she's now the first American to win Olympic gold in the sport.

Harrison, 22, won the women's under-78-kilogram division in London on Thursday, beating the United Kingdom's Gemma Gibbons in the finals of a 21-woman tournament.

Harrison, a Middletown, Ohio, native training in Massachusetts, became the United States' only Olympic champion in the sport -- woman or man. Ranked No. 4 in the world, she had upset top-ranked Brazilian Mayra Aguiar in the semifinals.

She started judo at roughly age 7. But to get to this point, she has said, she needed to overcome sexual abuse -- starting at age 13 -- by the person who was then coaching her.

"When I was 16, I told a close friend of mine, who immediately told my mother, and she immediately went to the police and pressed charges. The FBI got involved, and he's actually serving 10 years ... in prison," Harrison told CNN's Ashleigh Banfield on July 9, weeks before the Olympics began.

"Every day was a lie. Inside, I was in constant turmoil, but on the outside I was supposed to be this golden girl and so happy," Harrison said.

Harrison said she almost dropped judo because of the abuse. She said that it was not only "hard to deal with to be normal, but also to compete in the sport."

But she decided to stick with judo, going on to win gold at the 2008 Junior World Championships and the 2010 World Championships.

"You get to the point where you decide that you don't want to be a victim anymore and that you're not going to live your life like that," she said.