"My administration is going to stand with you, and fight alongside you, until the job is done," Obama said to cheers at Xavier University, a historically black, Catholic university that was badly flooded by the storm.
The president said there are still too many vacant lots, trailers serving as classrooms, displaced residents and people out of work. But he said New Orleanians have showed amazing resilience.
"Because of you," the president declared, "New Orleans is coming back."
Obama spoke five years to the day from when Hurricane Katrina roared onshore in Louisiana, tearing through levees and flooding 80 percent of New Orleans. More than 1,800 people along the Gulf Coast died, mostly in Louisiana.
Even as the region struggled to put despair behind it, hardship struck again this year in the form of the BP oil spill. More than 200 million gallons of oil surged into the Gulf of Mexico before the well was capped in mid-July. New Orleans' economy, heavily dependent on tourism and the oil and gas industry, was set back anew.
Standing in front of a large American flag with students arrayed behind him, Obama boasted of his administration's efforts to respond to the Gulf spill, saying one of his promises -- to stop the leak -- has been kept.
"The second promise I made was that we would stick with our efforts, and stay on BP, until the damage to the Gulf and to the lives of the people in this region was reversed," Obama said. "And this, too, is a promise we will keep."
But Obama's speech didn't offer any new plans for restoring the Gulf, bringing New Orleans' fast-disappearing wetlands back to life or cleaning up BP's spilled oil. Some residents had hoped Obama would take the opportunity to announce an early end to the deepwater drilling moratorium he enacted after the spill. But he made no mention of the moratorium, which people here say is costing jobs.
Obama did offer a list of accomplishments on Katrina recovery he said his administration has achieved, including helping move residents out of temporary housing, streamlining money for schools and restoration projects, and working to rebuild the poorly maintained levee system that failed the city when Katrina struck.
He promised that work on a fortified levee system would be finished by next year, "so that this city is protected against a 100-year storm. Because we should not be playing Russian roulette every hurricane season."
Implicit in Obama's remarks was an indictment of sorts against former President George W. Bush's administration for its handling of the crisis. Obama called Katrina and its aftermath not just a natural disaster but "a manmade catastrophe -- a shameful breakdown in government that left countless men, women and children abandoned and alone."
But Obama has faced questions of his own about how his administration handled the Gulf spill, including accusations officials moved too slowly and deferred too much to BP. The White House has scrambled repeatedly to right the response, pleasing Gulf Coast residents with a $20 billion victims' compensation fund Obama pushed BP to establish. But there is still plenty of skepticism among Gulf Coast residents about government promises, and Obama sought to alleviate that.
"In Washington, we are restoring competence and accountability," he said. "We're putting in place reforms so that never again in America is someone left behind in a disaster."
Arriving without any new policy announcements or benefits for the city, Obama appeared to hope in part that his mere presence would reassure residents they were not forgotten. For some, it might have been enough.
Before his speech Obama dropped in at the Parkway Bakery and Tavern, a local institution known for shrimp and roast beef po'boys, which was underwater after Katrina. "I appreciate you coming here," one woman told him. He responded with a hug.