"I'm so happy to be here in New Orleans," Foxx told the crowd.
He performed songs from his latest album, "Intuition," and tributes to Ray Charles and Michael Jackson, singing some of their biggest hits.
At the end, Foxx said a portion of his concert proceeds would be donated to Make It Right, the organization launched by actor-activist Brad Pitt to rebuild homes in the city's devastated Lower 9th Ward.
"This is just a drop in the bucket with what you guys really need out here, but it's a start," Foxx said. "You are not forgotten ... Keep your hopes up. You guys are resilient."
Though the amount of the donation was not disclosed, the concert drew some 8,000 to 10,000 people, and ticket prices ranged from $40-$64, said New Orleans Arena spokeswoman Laurel Hess.
Fans said they couldn't think of a better time than the anniversary of Hurricane Katrina for Foxx to make a trip to New Orleans.
"Everybody just wanted something to celebrate," Cassandra Larkin, whose New Orleans home flooded during Katrina, said after the concert. "This really lifted our spirits."
In a recent phone interview, Foxx said a little fun and laughter is just what New Orleans needs as the storm's fourth anniversary approaches. Katrina struck Aug. 29, 2005, and flooded 80 percent of the city.
"When you laugh, it does something for you," Foxx said. "You breathe."
Parts of the city have rebounded well, but recovery has been spotty and some neighborhoods are still in ruins. Foxx said he thinks New Orleans deserves ongoing attention as its residents continue rebuilding.
"It's important not to forget because lives are still wrecked," Foxx said. "Memorabilia that people collected all their lives, that's just gone. It's still gone."
Foxx, who grew up in Terrell, Texas, about 30 miles east of Dallas, said he used to visit New Orleans often while living in Texas and spent several months here in 2003 for the making of "Ray," the film in which Foxx won an Academy Award for his portrayal of singer-pianist Ray Charles.
"New Orleans has it's own pulse," Foxx said. "It's like it's own world, and when Katrina happened, I was devastated. ... Everybody was just uprooted. It was so tragic."