Oct. 30--CUPERTINO -- Apple CEO Tim Cook discussed his sexuality in an open forum for the first time Thursday, breaking a major barrier as the most prominent American CEO to publicly identify as gay.

In an essay published online Thursday morning by Bloomberg Businessweek, Cook called for human rights and equality, writing that he valued his privacy but hoped that he could help others by coming forward.

"While I have never denied my sexuality, I haven't publicly acknowledged it either, until now," Cook wrote. "So let me be clear: I'm proud to be gay, and I consider being gay among the greatest gifts God has given me."

Three years after succeeding Steve Jobs as Apple's leader, Cook has joined an extremely small circle of U.S. chief executives who are openly gay. While former American Eagle Outfitters CEO Robert Hanson, who now leads jewelry company John Hardy, has spoken out about life as a gay man in corporate America, Cook is believed to be the first CEO of a Fortune 500 company to publicly identify as gay.

Cook consulted with Apple's board before going public, Bloomberg Businessweek editor Josh Tyrangiel said on Bloomberg Television, citing a conversation with the Apple CEO. Art Levinson, chairman of Apple's board of directors, stressed that the company stands behind Cook.

"Tim has our wholehearted support and admiration in making this courageous personal statement," he said in a statement. "His decision to speak out will help advance the cause of equality and inclusion far beyond the business world."

Cook's move quickly drew praise from advocates for gay rights. Sarah Kate Ellis, president and CEO of the gay rights group GLAAD, said she is hopeful that Cook's decision to come out will drive greater public support for the LGBT community, particularly since he is from the South, where many states still ban same-sex marriage.

"When people who are highly regarded and well-respected come out, they change hearts and minds," Ellis said.

Cook prodded his home state of Alabama to embrace equality during his induction into the Alabama Academy of Honor earlier this week.

Cook may also empower more gay, lesbian and bisexual employees outside the C-suite to open up about their sexual orientation at work, Ellis said. A report released last year by Deloitte found that 83 percent of LGBT workers mask their identities at work. They struggle to do their best that work that way, Ellis said.

"Companies are starting to realize that there is a hard dollar cost when people aren't bringing their authentic selves to the office," she said.

The Human Rights Campaign also hailed Cook's move, saying he had made good use of his influence as leader of the world's most valuable company.

"Tim Cook's announcement today will save countless lives," Human Rights Campaign President Chad Griffin said in a statement. "Tim Cook is proof that LGBT young people can dream as big as their minds will allow them to, whether they want to be doctors, a U.S. Senator, or even CEO of the world's biggest brand."

Leaders of some of Apple's fiercest competitors also had praise for Cook. Microsoft CEO Satya Nadella posted on Twitter that he was "inspired" by Cook, and Facebook CEO Mark Zuckerberg and Chief Operating Officer Sheryl Sandberg applauded him on their social-networking site.

"Thank you Tim for showing what it means to be a real, courageous and authentic leader," Zuckerberg wrote.

Cook wrote in his essay that many people at Apple are aware of his sexual orientation and do not appear to have treated him any differently because of it. He said he is proud to work for such a tolerant company and will continue to push for equality.

"We'll continue to fight for our values, and I believe that any CEO of this incredible company, regardless of race, gender, or sexual orientation, would do the same," he wrote. "And I will personally continue to advocate for equality for all people until my toes point up."

In writing his piece, Cook found inspiration in the legacies of Robert Kennedy and Martin Luther King, whose portraits he keeps in his office at Apple. He stressed that his act had not put him in their league, but said he felt compelled to do his part in the fight for equality.

"We pave the sunlit path toward justice together, brick by brick," he wrote. "This is my brick."

Contact Julia Love at 408-920-5536 or follow her at Twitter.com/byJuliaLove.