In the candid video, Cavallo said growing up he felt the need to hide his sexuality, fearing being gay would get in the way of his dreams to play professional football.
"I was ashamed. Ashamed that I'd never be able to do what I love and be gay. Hiding who I truly am to pursue a dream I always wished for as a kid," Cavallo said.
"All I want to do is play football and be treated equally."
The 21-year-old midfielder said he was tired of living "a double life" and that it was "exhausting" trying to hide who he "truly is".
"The response and support I've received is immense. It's starting to make me think 'why have I been trying to hide this burden for so long?'"
In a statement posted on Twitter, Cavallo said he had been "fighting his sexuality" for six years and was "glad" to finally "put that to rest".
Cavallo said he wanted to inspire people and show it's okay to be gay and play football.
"I know there are other football players living in silence. I want to change this, to show everyone is welcome in the game of football and deserves the right to be their authentic self," Cavallo wrote.
A-League player Andy Brennan was the last Australian football player to come out as gay in 2019, becoming the first openly gay male football player in the country.
There are few openly gay male sports players in Australia. No known players in the men's AFL competition openly identify as gay, despite a number of players in the women's league coming out publicly.
In 1995, Ian Roberts became Australia’s first openly gay NRL player, but looking back, he regrets not “coming out sooner”.
“I realised after I came out how powerful it was, how much it changed people's lives and people's perspectives,” Roberts told The Feed.
“It gave some of the kids in the suburbs who’d been struggling a bit of a voice.”
A growing chorus of sports stars have applauded Cavallo on social media for coming out.
"Good for you @JoshuaCavallo," Matildas star Sam Kerr tweeted.
“It’s fantastic that Josh has found our sport and his club to be a safe place to share his sexuality," football player Alex Wilkinson said in a statement tweeted by Professional Footballers Australia.
"Despite progress made in sport and society, it takes a huge amount of courage to come out."
Cavallo hopes his message will help others in similar situations feel less alone.
"It is astonishing to know that there are currently no gay professional footballers who are out and actively playing, not only in Australia, but around the world," he said in a statement.
"Hopefully this will change in the near future. I hope that in sharing who I am, I can show others who identify as LGBTQ+ that they are welcome in the football community.