Anthony was voted in by players Friday during a meeting at All-Star weekend.
"We expect Carmelo to make an immediate contribution to our union," NBPA Executive Director Michele Roberts said in a statement. "He's passionate, has the respect of the players, and I'm sure he will have a strong point of view during the collective bargaining process."
Players and owners have until December to declare if they plan to opt out of the Collective Bargaining Agreement next July.
Anthony begins a three-year team immediately in replacing Willie Green, who served three years and isn't currently an active player. Anthony was active during the 2011 lockout that reduced the season to 66 games.
"I hope we can come to an agreement sooner rather than later. We don't want another work stoppage," Anthony said. "We've just got to sit down at the table. I think now it's talking about more important issues than what we've talked about in the past. We've got to just be transparent with one another."
If neither side opts out, the CBA would expire June 30, 2021. With revenues soaring a huge salary cap jump coming following the renewal of the NBA's national TV contracts, there is hope another work stoppage can be avoided. The sides have met in small groups.
"I think now is a time we should lay everything out on the table and come to an agreement," Anthony said.