Yusuke Kitamura hid his sexuality from colleagues for most of his career. It was only after joining one of Japan's oldest brokerages last year that he could tell them he was gay.

"It was so stressful having to lie, and I was hoping to come out at some point," Kitamura, 33, told a packed room of human resource professionals at an event on workplace diversity in Tokyo. "Now that I'm out, I've gone one step further to really communicate with people. I make it a point to talk about my private life."

Kitamura said he was closeted at his two previous jobs. What motivated his openness at Nomura Securities Co., where he's a training facilitator and an officer for diversity and inclusion, was its commitment not to discriminate against or harass others based on sexual orientation.