He revealed he made the decision to be open about his sexual orientation four years ago after hearing from children who were being bullied and abused and thinking of suicide.
“I am a private person and so I kept me to my small circle, and I started thinking that’s a selfish thing to do,” he told CNN.
“I needed to be bigger than that, I need to do something for them and show them that you can be gay and still go on and do some big jobs in life.
“I did not do it for other CEOs to come out. It wasn’t even in my mind. I was the first, which was kind of shocking, that I was the first.”
Asked he was proud of it, he replied: “I am very proud of it. To me it is God’s greatest gift to me, because by doing so I learned that I was in a minority.”
Mr Cook said the experience had provided him with “empathy for other people who are not in the majority”.
“My strong view is everybody should be treated with dignity and respect,” he said.
“And that’s the way I look at everyone regardless of their sexual orientation, regardless of their religion, their gender, their ethnic history, regardless of their gender identity, anything.”
He added: “At the end of the day, the problem comes down to one thing, treating people with dignity and respect.”
Mr Cook has also called for a rejection of intolerance and hate following the shooting at a synagogue in Pittsburgh on Saturday.
He tweeted a quote from Martin Luther King: “Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that.”