Landrieu has become the city's first white mayor since his father Moon Landrieu left the position in 1978.
His appointment ushers in hopes of a new era in a city still struggling to rebuild five years after Hurricane Katrina struck.
"Everybody feels like they have to have hope," Ralph Ampey, a local, said of the election. "Whatever they lost in the storm -- homes, furniture, property -- they hope they can get again."
The new mayor must manage billions of dollars in federal reconstruction aid and a depleted city treasury.
Moreover, city hall and the police department are rife with scandals.
According to the state treasurer, violence remains high, which is repelling potential investors from the city that has a lot more rebuilding to do.