Avery is said to be the first New York athlete to vocally support same-sex marriage.
The news was first reported by the New York Times.
In the Human Rights Campaign video, Avery, wearing a white shirt and glasses, says: "I'm Sean Avery and I'm a New Yorker for marriage equality. I treat everyone the way I expect to be treated and that applies to marriage."
After showing two shots of him in his Rangers gear -- with the statements "New Yorkers support full marriage equality" and "Do you?" appearing across the screen -- Avery finishes the clip by saying: "Committed couples should be able to marry the person they love. Join me in supporting marriage equality."
"Sean Avery knows what it means to be a leader -- on and off the ice," Brian Ellner, senior New York strategist for the Human Rights Campaign, a national gay-rights group, said in a released statement. "As the first professional athlete in the state to publicly support marriage equality, his voice is sure to resonate. Like a supermajority of New Yorkers, he believes in the freedom of all loving, committed couples to marry."
Avery was unavailable for comment.
Avery is one of many New York celebrities to take part in the campaign, which is focused on 30-second videos supporting same-sex marriage equality. Avery joins a list that includes Mayor Michael Bloomberg, U.S. senators Chuck Schumer and Kirsten Gillibrand, actress Julianne Moore and Barbara Bush, daughter of former president George W. Bush.
The New Yorkers for Marriage Equality campaign is part of the Campaign for New York Marriage, which is aiming for same-sex marriage equality in the state and help the federal marriage lawsuits. In 2009, the New York State Senate rejected a bill that would have allowed same-sex marriage.
According to the news release, a recent poll by the Siena Research Institute showed a record 58 percent support for marriage equality in New York state, with a record low of 36 percent against it.
Avery, 31, is a native of Pickering, Ontario, and has played with the Rangers for the past five seasons. In 2010-11, Avery -- an on-ice agitator who was suspended by the NHL in December 2008 for an off-color comment made about an opponent's girlfriend -- scored three goals and recorded 21 assists as the Rangers advanced to the playoffs.
Avery is not the first athlete to support same-sex marriage equality. Baltimore Ravens linebacker Brendon Ayanbadejo released a video asking for help in support of a same-sex marriage bill in Maryland.
Phoenix Suns players Jared Dudley and Grant Hill have filmed public service announcements addressing anti-gay language among teenagers that will be aired during the NBA conference finals, according to a news release on the Gay, Lesbian and Straight Education Network website.
No active player in any of the United States' four major sports leagues --- NFL, NHL, MLB and NBA -- has publicly announced he is gay.
Matt Ehalt is a regular contributor to ESPNNewYork.com.