The fifth seeded Indo-Zimbabwean pair beat the American-British pairing of Liezel Huber and Jamie Murray 7-6, 6-4 in the final.
The triumph increased Paes's tally of Grand Slam crowns to eight.
Games went with serve in the first set, which went to the tie-breaker, where Paes and Black fought back from 4-6 down to take the set at 8-6.
In the second set, Paes and Black got the crucial break in the fifth game, breaking Murray. They held serve comfortable thereafter to take the set and match.
Paes will also figure in the men's doubles final on Friday, when he and his Czech partner Lukas Dlouhy take on the Bryan twins Mike and Bob of the United States.
In 1999, Paes had partnered Mahesh Bhupathi and Lisa Raymond to win the men's doubles and mixed doubles crowns at Wimbledon.
Image: Paes and Black with the US Open mixed doubles trophy.
Photograph: Matthew Stockman/Getty Images