Three men in their 20s were the shooters' intended targets, police said. They were standing in a driveway when a white Cadillac sedan approached at about 1:30 p.m. and one of the people in the car started firing, hitting the men, and wounding a 21-year-old woman and the baby who were walking to a nearby store.
Police found a 23-year-old man lying in the rear driveway, the 20-year-old a short distance away, and the infant with gunshot wounds. They were all taken to a hospital. The 20-year-old later died and the baby was listed in good condition, said police spokeswoman Officer Shereese Harper.
The woman hit in the foot and another 20-year-old man drove themselves to the hospital and were in stable condition, police said.
New Orleans Mayor Mitch Landrieu was at the scene and called it "another senseless shooting."
"It just defies common sense," he told reporters.
Investigators said the 23-year-old man discarded a semiautomatic weapon and narcotics that were found a few feet from his body.
Capt. Bob Bardy said one man was shot in the chin, another in the back and a third in the arm. It wasn't clear where the child was hit.
Authorities had no immediate report on suspects, motives or the names of those wounded.
(This version CORRECTS Updates with one of the victims dying. Corrects baby's age to 3 months. Deletes references to exchange of gunfire.)