Gus Johnston was an elite Victorian hockey player but for half his life harboured the secret of being gay.
"In that time, not once did I stand up for what I believed in, for who I am, when the people around me behaved in a homophobic way," the 32-year-old told an audience at Victoria's parliament house on Tuesday.
"I dipped my head, I said nothing, I fell silent."
Mr Johnston was speaking at the launch of the No to Homophobia campaign, which aims to clamp down on discrimination against gay, lesbian, bisexual and transgender people.
Mr Johnston said he was ashamed to have been complicit in homophobic behaviour but decided a year ago to come out publicly via YouTube.
"I wasn't going to stand by and let these words go unchallenged," he said. "Whenever homophobia is accepted and defended, it reinforces a great wall of discrimination ... a lonely place where I spent nearly half my life, where I struggled with my own self-worth and battled with demons no one least of all a young person should have to face.
"But they do because we let them." Launching the campaign, Victorian Mental Health Minister Mary Wooldridge said it is everyone's responsibility to take action. "This is a call to action in relation to saying no to homophobia," she said.
Victoria Police Chief Commissioner Ken Lay said laws are in place to protect Victorians from all forms of violence, bullying, harassment or intimidation.
Ian Bell, chairman of the Pink Magpies, an official Collingwood Football Club support group, said its involvement in AFL culture might spur others to realise it's acceptable to be footy-mad and gay.
"Somewhere out there in a country town or maybe in an outer suburb or inner, some boy or girl might go, `It's OK to be who I am, it's OK to be gay and a footy supporter'."
Watch a homophobia TV ad on YouTube: