American basketball star Jason Collins has spoken about his sexuality, confirming he’s gay in an article to Sports Illustrated magazine.

He’s the first openly gay athlete in one of the big-four American team sports to come out as an active player.

Collins, who has most recently played for the Washington Wizards and the Boston Celtics, wrote: “I’m a 34-year-old NBA center. I’m black. And I’m gay.

“I didn’t set out to be the first openly gay athlete playing in a major American team sport. But since I am, I’m happy to start the conversation. I wish I wasn’t the kid in the classroom raising his hand and saying, ‘I’m different.’ If I had my way, someone else would have already done this. Nobody has, which is why I’m raising my hand.”

Collins has played for six teams over 12 seasons. He said his final motivation for coming out was being unable to participate in a gay pride parade in Boston last year.

“I realized I needed to go public when Joe Kennedy, my old roommate at Stanford and now a Massachusetts congressman, told me he had just marched in Boston’s 2012 Gay Pride Parade,” Collins said. “I’m seldom jealous of others, but hearing what Joe had done filled me with envy. I was proud of him for participating but angry that as a closeted gay man I couldn’t even cheer my straight friend on as a spectator. If I’d been questioned, I would have concocted half truths. What a shame to have to lie at a celebration of pride. I want to do the right thing and not hide anymore. I want to march for tolerance.”

Collins, who is professionally a free agent, having played 11 seasons in the NBA with six teams, said he had tried to suppress his feelings through relationships with women.

“When I was younger I dated women. I even got engaged,” he said. “I thought I had to live a certain way.

“I thought I needed to marry a woman and raise kids with her. I kept telling myself the sky was red, but I always knew it was blue.”

In February 2007, after his retirement from the NBA, John Amaechi became the first former NBA player to come out publicly after doing so in his memoir Man in the Middle.

On Monday afternoon, Amaechi tweeted: “Congratulations to Jason – society couldn’t hope for a more eloquent & positive role model.”