Bruce Jenner said that "for all intents and purposes, I am a woman" in an interview broadcast Friday night.
"I was not genetically born that way," Jenner said in an interview with ABC News' Diane Sawyer on "20/20." "As of now -- I have all the male parts and all that kind of stuff ... we still identify as female. And that's very hard for Bruce Jenner to say. Because why? I don't want to disappoint people."
Jenner also told Sawyer: "My brain is much more female than it is male. It's hard for people to understand that. But that's what my soul is."
Early in the interview, Jenner took out a ponytail, allowing long hair to flow. Jenner also fought back tears even before the interview started.
Jenner, 65, won the 1976 Olympic decathlon, setting a world record and becoming an international sports star. Jenner later became an actor in a number of TV movies, a race car driver (winning the 12 Hours of Sebring in 1986) and a successful businessman. Jenner married his third wife, Kris Kardashian, in 1991, and became part of the E! network series "Keeping Up With The Kardashians" in 2007. (Kris and Bruce Jenner were divorced in December 2014).
Jenner said he told his first two wives about the gender confusion, and it was a factor in the breakup of his second marriage.
Jenner has six biological children (Burt, Cassandra, Brandon, Brody, Kendall and Kylie) and four step children (Kourtney, Kim, Khloe and Rob Kardashian). He said he told them, and his mother, recently. His ex-wives and sister were the only ones who previously knew.
"They all cried. Mainly because they didn't want anybody to hurt dad," Jenner told ABC News. "They are very protective of me."
Asked about the reality show, Jenner told Sawyer: "The one real, true story in the family was the one I was hiding and nobody knew about it. And I could not tell that story."
As a young boy, Jenner felt an urge to try on his mother's and sister's dresses.
"I marked the closet so when I put it back I could put it all back, everything back in the exact same spot so I wouldn't get caught," Jenner said. "And, at the time, I didn't know why I was doing it besides it just made me feel good."
As an adult, Jenner wore women's clothing in hotel rooms when he traveled often as a motivational speaker.
"I'd literally go up into the hotel room, change [into women's] clothes, and walk around," Jenner said.
Looking back at footage of the 1976 Olympics, Jenner told Sawyer the person who won the decathlon was "running away from who I was." Jenner told Sawyer about considering a transitioning in the 1980s, even taking hormones "for almost five years."
Jenner self-identifies as "her," but not by a specific name. But Jenner was comfortable using the pronouns "he" and "him," and ABC News used them throughout the broadcast.
Jenner wanted to make clear to viewers that gender identity and sexuality were separate things.
"I am not gay," Jenner said. "I am, as far as I know, heterosexual. I've always been with a woman, raising kids."
On a relationship with the transgender community, Jenner said: "I would like to work with this community to get this message out. They know a lot more than I know ... I am not a spokesman for the community."
Athlete Ally, an organization activating athletes to support lesbian, gay, bisexual and transgender inclusion and equality, congratulated Jenner after the interview concluded.
"Jenner's interview today made me think about how long it took for her to publicly live her truth," former NFL player and Ally board member Brendon Ayanbadejo said as part of a statement released by the organization. "And, I think about what I could have done -- what we all could have done -- to make today's announcement easier. Allies need to understand that every transgender individual's journey is personal. But, at the end of the day, it's on us to help end stigma. Congratulations Bruce. We respect and support you!"
Jenner said he hopes that speaking publicly about the gender issues would do some good in the world and vigorously denied that the interview was some sort of publicity stunt to promote the Kardashian reality TV show.
"What I'm doing is going to do the world some good," Jenner said. "And we're going to change the world ... I really firmly believe that."
After the ABC interview aired, E! announced an eight-part documentary profiling Jenner "living his life as a transgender woman." It will begin airing in July.
Jenner was involved in a February car accident that killed a woman in Malibu. The interviews were filmed before the accident. ABC said Jenner couldn't comment on the incident.
Jenner's mother, Esther, was shown in the interview, saying, "I want you to be happy and I love you."
She said she was proud of Jenner at the 1976 Olympics, adding: "I never thought I could be more proud of you. But I'm learning I can be."
Jenner has gone back to say he was sorry to people in his life hurt by the gender identity issues.
"I've apologized to everybody," Jenner said. "I've apologized my whole life."
Jenner's first two wives offered messages of support; Kris Kardashian told ABC she had no comment but tweeted after the interview aired, "Not only was I able to call him my husband for 25 years and father of my children, I am now able to call him my hero."
Sawyer asked Jenner if there was anything that should be asked. Jenner said, "Are you gonna be OK?"
Sawyer asked it.
Said Jenner: "Yeah. I hope I'm gonna be OK. I feel like I'm going to be OK ... 2015 is going to be quite a ride. Quite a ride."
Information from The Associated Press is included in this report.