The public declaration, in an essay written for Bloomberg Businessweek, makes Cook the highest-profile business CEO to come out as gay.
Cook said that while he never denied his sexuality, he never publicly acknowledged it, either. The executive said that for years he's been open with many people about his sexual orientation and that plenty of his Apple colleagues know he is gay.
Cook wrote in the column published Thursday that it wasn't an easy choice to publicly disclose that he is gay, but that he felt the acknowledgement could help others.
"I've come to realize that my desire for personal privacy has been holding me back from doing something more important,'' he wrote.
Three days ago, Cook challenged his home state of Alabama to better ensure the rights of the lesbian, gay, bisexual and transgender community.
Alabama is among the states that do not recognize same-sex marriage, and it also doesn't offer legal protections on the basis of sexual orientation or gender identity. Cook is a native of Robertsdale, Alabama, and attended Auburn University.
"I consider being gay among the greatest gifts God has given me,'' Cook wrote in the essay Thursday.
The executive said that "being gay has given me a deeper understanding of what it means to be in the minority and provided a window into the challenges that people in other minority groups deal with every day.''
Cook said he's been lucky to work for a company that "loves creativity and innovation and knows it can only flourish when you embrace people's differences.''
Cook succeeded Apple founder Steve Jobs as CEO of Apple Inc. in 2011.
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