The shooting happened around 2:45 a.m., two blocks from Jackson Square around the corner from Pat O'Brien's.
Witnesses at the scene early Sunday said an angry-sounding man opened fire on one man then continued shooting into the crowd on the street.
"Just turned around and he started shooting at the crowd. He seemed pissed off at some dude, pulled the gun out and started shooting at the guy then turned around on the crowd and started shooting at us," one witness, whose name wasn't reported, told WWL-TV.
The most seriously injured of those shot was a woman who was in critical condition.
"These kinds of incidents will not go unanswered," New Orleans Mayor Mitch Landrieu said. "NOPD was in the immediate vicinity at the time of the incident, and I am confident that between video evidence and eyewitness accounts, we will bring the perpetrators to justice. Our crime fighting efforts have brought murders in the city of New Orleans to a historic nearly 30-year low. But on days like today, the statistics don't matter because every life is precious -- from the 9th Ward to the French Quarter. We will not rest until every corner of this city is safe."